Respiratory Ventilation System with Gas Sparing Valve Having Optional CPAP Mode and Mask for Use with Same

ABSTRACT

A system for delivering gas to a patient. The system includes a gas control unit, a breathing circuit, a control switch, and a patient interface. The gas control unit has a main gas outlet. The breathing circuit has a main gas line having a first end. The first end of the main gas line is coupled to the main gas outlet. The control switch may be a pneumatic switch, in which case the breathing circuit further has a pilot control line for pneumatically controlling the gas control unit to deliver gas to the main gas line via the main gas outlet. The control switch may be an electrical switch, in which case the breathing circuit may use electrical control of the gas delivery or electrical and pneumatic control of the gas delivery. Other embodiment of the gas control unit may include a continuous positive airway pressure branch.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. application Ser. No.13/680,793, filed Nov. 19, 2012, entitled “Respiratory VentilationSystem with Gas Sparing Valve having Optional CPAP Mode and Mask for Usewith Same,” which application claims benefit of priority of U.S.Provisional Application No. 61/561,465, filed Nov. 18, 2011. Each of theabove-identified related applications are incorporated herein byreference.

FIELD OF THE INVENTION

The present invention relates, generally, to a respiratory ventilationsystem that controls gas delivery to a patient and, particularly, to arespiratory ventilation system that utilizes a gas sparing valve toconserve gas. More particularly, the present invention relates to apneumatically controlled respiratory ventilation system that utilizes apilot circuit to control gas flow in a main gas supply circuit tothereby conserve gas supplied to a patient.

BACKGROUND OF THE INVENTION

Ventilation is the physiologic process of moving a gas into(inspiration) and out of (expiration) the lungs of a patient, therebydelivering oxygen to organs of the patient and excreting carbon dioxide.During spontaneous ventilation, i.e. unassisted breathing, negative(sub-atmospheric) pressure is created within the chest of the patient.As a result, gas moves into the lungs of the patient.

In the practice of medicine, there is often a need to substitutemechanical ventilatory support for the spontaneous breathing of apatient. Mechanical ventilation is a method to mechanically assist orreplace spontaneous breathing. This may involve a machine called aventilator. Alternatively, the breathing of the patient may be assistedby a physician or other suitable person compressing a bag or set ofbellows. In positive pressure ventilation, air (or another gas mix,e.g., oxygen mix) is pushed into the trachea of the patient. Thepositive pressure forces air to flow into the airway to expand and fillthe lungs until the inspiration breath is terminated. Subsequently, theairway pressure drops, and the elastic recoil of the chest wall andlungs push the tidal volume, the breath, out through passive expirationor exhalation.

Mechanical ventilation may be necessary during respiratory failure orwhen patients are placed under anesthesia. Particular examples arepatients with acute lung injury, including acute respiratory distresssyndrome (ARDS); apnea with respiratory arrest, including cases fromintoxication; chronic obstructive pulmonary disease (COPD); acuterespiratory acidosis; respiratory distress; hypoxemia; hypotensionincluding sepsis; shock; congestive heart failure; and neurologicaldiseases such as Muscular Dystrophy and Amyotrophic Lateral Sclerosis;etc.

SUMMARY OF THE INVENTION

In accordance with an exemplary aspect of the present invention, thereis provided a system for delivering gas to a patient. The systemincludes a gas control unit, a breathing circuit, a pilot controlswitch, and a patient interface. The gas control unit includes an outlethaving a main gas line outlet. The gas control unit further includes agas sparing circuit having a primary branch coupled to the main gas lineoutlet. The primary branch includes a gas sparing valve for controllinga flow of gas through the primary branch. The breathing circuit includesa main gas line having a first end and a second end. The first end ofthe main gas line is coupled to the main gas line outlet. The pilotcontrol switch is for selectively causing the gas sparing valve toprovide the flow of gas to the main gas line via the main gas lineoutlet. The patient interface is coupled to the second end of the maingas line of the breathing circuit.

In accordance with another exemplary aspect of the present invention,there is provided a pneumatic system for delivering gas to a patient.The pneumatic system includes a gas control unit, a breathing circuit, apilot control switch, and a patient interface. The gas control unitincludes an outlet having a pilot control line outlet and a main gasline outlet. The breathing circuit includes a pilot control line havinga first end and a second end. The breathing circuit also includes a maingas line having a first end and a second end. The first end of the pilotcontrol line is coupled to the pilot control line outlet, and the firstend of the main gas line is coupled to the main gas line outlet. Thepilot control switch allows a user to selectively cause the gas controlunit to provide gas to the main gas line via the main gas line outlet.The patient interface is coupled to the second end of the main gas lineof the breathing circuit.

In accordance with a further exemplary aspect of the present invention,there is provided a pneumatic system for delivering gas to a patient.The pneumatic system includes a gas control unit, which includes anoutlet having a pilot control line outlet and a main gas line outlet anda gas sparing circuit. The gas sparing circuit includes a primary branchcoupled to the main gas line outlet, a pilot control branch coupled tothe pilot control line outlet, a pneumatic control valve disposed in theprimary branch, the pneumatic control valve comprising a control input,and a timer circuit comprising an output coupled to the control input ofthe pneumatic control valve. The pneumatic system also includes abreathing circuit having a pilot control line a main gas line. The pilotcontrol line includes a first end and a second end, and the main gasline includes a first end and a second end. The first end of the pilotcontrol line is coupled to the pilot control line outlet, and the firstend of the main gas line is coupled to the main gas line outlet. Thepneumatic system further includes a pilot control switch for selectivelycausing the pneumatic control valve to open to provide gas to the maingas line via the main gas line outlet and for activating the pneumatictimer to close the pneumatic control valve after a predetermine amountof time. A patient interface is coupled to the second end of the maingas line of the breathing circuit.

In accordance with still another exemplary aspect of the presentinvention, there is provided a pneumatic system for delivering gas to apatient. The pneumatic system includes a gas control unit having anoutlet including a pilot control line outlet and a main gas line outlet.The pneumatic system also includes a breathing circuit, a pilot controlswitch, and an endotracheal hand piece configured to couple thebreathing circuit to an endotracheal tube. The breathing circuitincludes a pilot control line having a first end and a second end and amain gas line having a first end and a second end. The first end of thepilot control line is coupled to the pilot control line outlet, and thefirst end of the main gas line is coupled to the main gas line outlet.The pilot control switch allows for a user to selectively cause the gascontrol unit to provide gas to the main gas line via the main gas lineoutlet.

In accordance with yet another exemplary aspect of the presentinvention, there is provided a pneumatic system for delivering gas to apatient. The pneumatic system includes a gas control unit, a breathingcircuit, a pilot control switch, and a patient interface. The gascontrol unit includes a pilot branch, a primary branch, a continuouspositive airway pressure (CPAP) branch, and an outlet having a pilotcontrol line outlet coupled to the pilot branch and a main gas lineoutlet coupled to the primary branch and the CPAP branch. The gascontrol unit further includes a directional flow control valve forselecting for gas to flow to the main gas line outlet via the primarybranch or the CPAP branch. The breathing circuit includes a pilotcontrol line having a first end and a second end and a main gas linehaving a first end and a second end. The first end of the pilot controlline is coupled to the pilot control line outlet, and the first end ofthe main gas line is coupled to the main gas line outlet. The pilotcontrol switch allows a user to selectively cause the gas control unitto provide gas to the main gas line via the main gas line outlet. Thepatient interface is coupled to the second end of the main gas line ofthe breathing circuit.

In accordance with another aspect of the present invention, there isprovided a gas control unit. In one embodiment, the gas control unitincludes an outlet having a main gas line outlet, and a gas sparingcircuit including a primary branch coupled to the main gas line outletand a gas sparing valve for controlling a flow of gas through theprimary branch in response to a selective control. In anotherembodiment, the gas control unit includes an inlet line, an outlet porthaving a pilot control line outlet and a main gas line outlet, and a gassparing circuit. The gas sparing circuit includes a primary branchcoupled to the inlet line and the main gas line outlet, a pilot controlbranch coupled to the inlet line and the pilot control line outlet, anda pneumatic control valve disposed in the primary branch. The pneumaticcontrol valve includes an input coupled to the inlet line, an outputcoupled to the main gas line outlet, and a control input coupled to thepilot branch. The pneumatic control valve is configured to be actuatedafter occlusion of the pilot control branch to allow gas to flow throughthe primary branch to the main gas line outlet.

In accordance with yet another embodiment of the present invention,there is provided a valve system having a one-way breathing valve forproviding primary gas from a source system to a patient upon inhalation,a one-way exhaust valve for exhausting gas from the patient uponexhalation, and an air inlet valve for inletting gas from atmospherewhen demand for gas from the patient during inhalation exceeds the gasfrom the source system.

In accordance with yet another embodiment of the present invention,there is provided a patient interface for use with a gas sparingcircuit. The patient interface may include a patient mask interface oran endotracheal tube connection. The patient interface may also includea vent port for exhalation by a user of the patient interface during acontinuous positive airway pressure (CPAP) mode.

BRIEF DESCRIPTION OF THE DRAWINGS

For the purpose of illustration, there are shown in the drawings certainembodiments of the present invention. In the drawings, like numeralsindicate like elements throughout. It should be understood, however,that the invention is not limited to the precise arrangements,dimensions, and instruments shown. In the drawings:

FIG. 1 illustrates an exemplary embodiment of a system for deliveringgas to a patient, the system comprising a gas control unit, a disposablebreathing circuit, and a mask, the gas control unit comprising a gassparing circuit comprising a primary branch and a pilot control branch,the primary branch comprising a gas sparing valve, in accordance with anexemplary embodiment of the present invention;

FIG. 2 illustrates an exemplary embodiment of an alternative system fordelivering gas to a patient, the alternative system comprising a gascontrol unit, a disposable breathing circuit, and a mask, the gascontrol unit comprising a gas sparing circuit comprising a primarybranch, a pilot control branch, and a continuous positive airwaypressure (CPAP) branch, the primary branch comprising a gas sparingvalve, in accordance with an exemplary embodiment of the presentinvention;

FIG. 3 illustrates an exemplary block diagram of the exemplaryembodiment of the system of FIG. 1, in accordance with an exemplaryembodiment of the present invention;

FIG. 4 illustrates an exemplary block diagram of the exemplaryembodiment of the system of FIG. 2, in accordance with an exemplaryembodiment of the present invention;

FIGS. 5A through 5C illustrate various exemplary embodiments of anexternal gas port used with the gas control units of FIGS. 1 and 2, theexternal gas port comprising pilot and main outlets, in accordance withan exemplary embodiment of the present invention;

FIG. 6 illustrates an exemplary simplified block diagram of theexemplary embodiment of the gas sparing circuit of FIG. 1 or FIG. 2, inaccordance with an exemplary embodiment of the present invention;

FIG. 7A illustrates a graph of exemplary pressures at various points inthe exemplary simplified block diagram illustrated in FIG. 6, inaccordance with an exemplary embodiment of the present invention;

FIG. 7B illustrates a graph of exemplary gas flow through the primarybranch and the pilot control branch in the gas sparing circuit of FIG. 1or FIG. 2, in accordance with an exemplary embodiment of the presentinvention;

FIGS. 8A and 8B illustrate exemplary operation of an exemplaryembodiment of a pilot control switch used to selectively occlude thepilot control branches of FIGS. 1 and 2, in accordance with an exemplaryembodiment of the present invention;

FIGS. 8C through 8E illustrate various views of an exemplary alternativeembodiment of a disposable breathing circuit, in accordance with anexemplary embodiment of the present invention;

FIG. 9 illustrates an exemplary embodiment of a gas sparing circuitcomprising a timer control for main-flow on-time control, in accordancewith an exemplary embodiment of the present invention;

FIG. 10 illustrates another exemplary embodiment of a gas sparingcircuit comprising a timer control for main-flow on-time and off-timecontrol, in accordance with an exemplary embodiment of the presentinvention;

FIGS. 11A and 11B illustrate exemplary views of an exemplary embodimentof a timer-based trigger used to selectively occlude the pilot controlbranches of FIGS. 1 and 2, the timer-based trigger providing main-flowon-time control, in accordance with an exemplary embodiment of thepresent invention;

FIG. 12 illustrates an exemplary embodiment of a mask connection for usewith a gas sparing circuit, the mask connection comprising a spontaneousbreath valve, in accordance with an exemplary embodiment of the presentinvention;

FIG. 12A illustrates an exemplary alternative embodiment of thespontaneous breath valve of FIG. 12, in accordance with an exemplaryembodiment of the present invention;

FIGS. 12B and 12C respectively illustrate side cross-sectional and topviews of the exemplary embodiment of the mask connection of FIG. 12connected to the exemplary alternative embodiment of the disposablebreathing circuit of FIG. 8C, in accordance with an exemplary embodimentof the present invention;

FIG. 13 illustrates an exemplary embodiment of a hand piece forcontrolling operation of a gas sparing circuit, the hand piececomprising a pilot control switch, in accordance with an exemplaryembodiment of the present invention;

FIG. 13A illustrates an exemplary embodiment of the pilot control switchof FIG. 13, in accordance with an exemplary embodiment of the presentinvention;

FIG. 14 illustrates an exemplary embodiment of a system incorporatingthe hand piece of FIG. 13, in accordance with an exemplary embodiment ofthe present invention;

FIG. 15 illustrates an exemplary embodiment of an endotracheal handpiece for control operation of a gas sparing circuit, in accordance withan exemplary embodiment of the present invention;

FIGS. 16A and 16B illustrate exemplary alternative embodiments of maskswith integrated hand pieces for control operation of a gas sparingcircuit, in accordance with an exemplary embodiment of the presentinvention;

FIG. 17 illustrates an exemplary embodiment of a mask with a CPAP portfor use with a system providing resuscitation and CPAP air delivery, inaccordance with an exemplary embodiment of the present invention;

FIG. 18 illustrates another view of the exemplary embodiment of the handpiece of FIG. 13 showing the pilot control switch attached to the mask,in accordance with an exemplary embodiment of the present invention;

FIG. 19 illustrates an exemplary alternative embodiment of a hand piecefor controlling operation of a gas sparing circuit, in accordance withan exemplary embodiment of the present invention;

FIGS. 20A through 20C illustrate various views of another alternativeembodiment of a hand piece for controlling operation of a gas sparingcircuit, in accordance with an exemplary embodiment of the presentinvention;

FIG. 21 illustrates a view of an exemplary housing for the gas controlunit of FIG. 2, in accordance with an exemplary embodiment of thepresent invention;

FIGS. 22A through 22C illustrate various views of another exemplaryembodiment of a mask with a CPAP port for use with a system providingresuscitation and CPAP air delivery, in accordance with an exemplaryembodiment of the present invention;

FIGS. 23A through 23F illustrate various views of various components ofa combination of the mask of FIGS. 22A through 22C connected to the maskconnection of FIG. 12, which is connected to the exemplary alternativeembodiment of the disposable breathing circuit of FIG. 8C, in accordancewith an exemplary embodiment of the present invention;

FIG. 24 illustrates an exemplary block diagram of an exemplaryembodiment of a system for delivering gas to a patient using electricalsolenoid and electrical switch control of a pilot control branch, inaccordance with an exemplary embodiment of the present invention;

FIG. 25 illustrates an exemplary block diagram of an exemplaryembodiment of a system for delivering gas to a patient using electricalswitch control of a gas sparing valve, in accordance with an exemplaryembodiment of the present invention;

FIG. 26A illustrates an exemplary block diagram of an exemplaryembodiment of a gas sparing using selectable manual pilot line controland electrical timer control of a gas sparing valve, in accordance withan exemplary embodiment of the present invention;

FIG. 26B illustrates an exemplary block diagram of an exemplaryembodiment of a gas sparing circuit of using selectable manual pilotline control of a gas sparing valve and electrical timer control of thegas sparing valve contained in an external, removable module, inaccordance with an exemplary embodiment of the present invention;

FIG. 27 illustrates an exemplary block diagram of an exemplaryembodiment of a gas sparing circuit using selectable manual pilot linecontrol of a gas sparing valve and pneumatic timer control of the gassparing valve, in accordance with an exemplary embodiment of the presentinvention;

FIG. 28 illustrates an exemplary block diagram of an exemplaryembodiment of a gas sparing circuit using a timer control for main-flowon-time and off-time control implemented with two on-time timers, inaccordance with an exemplary embodiment of the present invention;

FIG. 29 illustrates an exemplary block diagram of an exemplaryembodiment of a gas sparing circuit using selectable manual pilot linecontrol of a gas sparing valve and pneumatic timer for main-flow on-timeand off-time control utilizing two on-time timers, in accordance with anexemplary embodiment of the present invention;

FIG. 30 illustrates an exemplary block diagram of an exemplaryembodiment of a gas sparing circuit comprising a pressure surge dampingelement to eliminate pressure surges when a gas sparing valve is opened,in accordance with an exemplary embodiment of the present invention;

FIG. 30A illustrates an exemplary embodiment of the pressure surgedampening element of FIG. 30, in accordance with an exemplary embodimentof the present invention;

FIG. 31A illustrates a graph of exemplary gas pressure through theprimary branch in the exemplary embodiment of the gas sparing circuitillustrated in FIG. 3, in accordance with an exemplary embodiment of thepresent invention;

FIG. 31B illustrates a graph of exemplary gas pressure through theprimary branch in the exemplary embodiment of the gas sparingillustrated in FIG. 30, in accordance with an exemplary embodiment ofthe present invention; and

FIG. 32 illustrates an exemplary embodiment of an endotracheal handpiece for control operation of a gas sparing circuit including a CPAPport for CPAP functionality, in accordance with an exemplary embodimentof the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Conventional pneumatic flow circuits or devices do not allow forresuscitation gas flow to be controlled pneumatically. Although it ispossible to put a spring-actuated flow control valve near an outletpoint of a conventional pneumatic flow circuit, this placement of theflow control valve would make the pneumatic flow circuit complicated andbulky. Further, because the portion of the pneumatic flow circuitconnected to the patient may be disposable, placement of the flowcontrol valve on the disposable portion would result in a possiblyunacceptable increase in cost of the disposable portion. Further,locating the flow control valve in the disposable portion may not allowfor a pop off and peak inspiratory pressure (PIP) pressure control valvearrangement with a gauge remotely located within the pneumatic flowcircuit. If located after the flow control valve in the disposableportion, such components would make the disposable portion bulky andexpensive. Locating such pressure control valve arrangement at thepatient site may increase the size and cost of the disposable portion.

Conventional manual and pneumatic devices suffer from numerousdisadvantages, such as continuous large gas flows, no flow control, andno pressure control. In addition, some devices waste significant amountsof compressed gases, thereby causing compressed gas tanks to have verylimited life. Furthermore, conventional pneumatic devices do not offerthe option of delivering fixed, user set flow rates in a continuouspositive airway pressure (CPAP) mode through a combined resuscitationand CPAP unitary breathing circuit and mask assembly.

An exemplary embodiment of the present invention provides a gas sparingcircuit that minimizes the continuous large gas flows from conventionalpneumatic devices while allowing for user activation of the large gasflows required for resuscitation. In addition, the gas sparing circuitallows for precise pressure and volume control to the patient currentlynot available in conventional resuscitation devices.

Referring now to FIG. 1, there is illustrated a block diagram of asystem, generally designated as 100, for delivering gas to a patient, inaccordance with an exemplary embodiment of the present invention. Thesystem comprises a gas control unit 110, a disposable breathing circuit120, and a patient mask 130. The disposable breathing circuit 120operates in a resuscitation mode to deliver resuscitating gas to apatient (not illustrated) via a patient mask 130 worn by the patient. Afirst end 121 of the disposable breathing circuit 120 is coupled to thegas control unit 110, and a second end 122 of the disposable breathingcircuit 120 is coupled to a connection port 131 of the patient mask 130to deliver gas to the patient during inhalation. The mask 130 interfaceswith the patient via a patient-mask interface 132. A pilot controlswitch 125 is disposed near the end 122 of the disposable breathingcircuit 120 for selective control of main gas delivery flow to thepatient. In one exemplary embodiment, the gas comprises air. In anotherexemplary embodiment, the gas comprises an oxygen mixture. Although notillustrated, it is to be understood that, in an exemplary embodiment,the mask 130 may include one or more exhaust ports to allow forexhalation by the patient.

The basic principle of operation for the system 100 is to utilize apneumatic pilot controlled valve in the gas control unit 110. Asdiscussed below with respect to FIG. 3, the pneumatic pilot controlledvalve is coupled to a high pressure, low flow small diameter pilotcontrol circuit that is controlled by a user, such as a medicalpractitioner, to control a high pressure, high flow main gas circuit toprovide on-demand high flow to the patient when needed and to only allowa small trickle pilot flow when there is no main gas demand. Thiscontrol conserves gas supply by closing the main gas circuit when notdemanded. Demanded gas flows at a rate of 35 to 50 liters/minute. Atrickle flow of 1-3 liters/minute flows through the pilot controlcircuit when there is no main gas demand or need for gas by the patient.In an exemplary embodiment, pilot gas flows through the pilot controlcircuit at not more than 2 liters per minute.

Accordingly, the gas control unit 110 comprises a gas inlet 111 and agas port 112 comprising a pilot control port 116 and a main gas port117. (As used herein, the terms “port,” “outlet,” and “outlet port” maybe used interchangeably herein as context permits. The same holds truefor the terms “port,” “inlet,” and “inlet port” and the terms “primarygas,” “main gas,” and “patient gas.”) The gas inlet 111 is coupled to agas source (supply), such as a wall source, compressed gas line, or acanister of compressed breathing gas. The pilot control port 116 iscoupled to a pilot control line, and the main gas outlet 117 is coupledto a high pressure, high flow main gas line. The gas control unit 110includes a flow rate control selection means 115 to allow the user toselect a desired flow rate in the main gas line. An example of selectionmeans 115 is a flow control valve. The gas control unit 110 furthercomprises a flow meter 113 to display the current flow rate of the gasthrough the inlet 111 and a pressure gauge 114 to display the currentgas pressure in the main gas outlet 117 being delivered to the patient.The gas control unit 110 also comprises a pop off maximum pressurerelief valve 118 and a peak inspiratory pressure (PIP) relief valve 119.Although the gas control unit 110 is configured for receiving gas froman external gas source via the inlet 111, other exemplary embodimentsare contemplated. For example, it is contemplated that the gas controlunit 110 may comprise an internal gas source, such as an internal tank,for storing primary gas, or internal gas pump.

The maximum pressure relief valve 118 allows the user to set the maximumpressure that can build up in the gas control unit 110 and thedisposable breathing circuit 120 before safely venting to atmosphere. Itensures that pressure in the system 100 does not exceed this maximumpressure. Thus, the valve 118 protects the patient from the high maingas source outlet pressure, typically 50 psi.

The peak inspiratory pressure (PIP) valve 119 allows the user to set thepeak inspiratory pressure the patient will be exposed to. Thus, the PIPvalve 119 protects the patient from gas delivery pressures above PIPpressure. In the event that gas pressure at the main gas outlet 117 isabove PIP, the PIP valve 119 opens to maintain the pressure at theoutlet 117 at the PIP setting to ensure that the pressure of the gasdelivered to the mask 130 is safe for the patient's lungs. The valve 118acts as a safety valve in the event that the PIP valve 119 fails toproperly operate.

Referring now to FIG. 3, there is illustrated a block diagram of a gassparing circuit 300 comprising the gas control unit 110, the disposablebreathing circuit 120, and the patient mask 130, in accordance with anexemplary embodiment of the present invention. The gas sparing circuit300 uses all of the components illustrated in FIG. 1 and additionalcomponents, as illustrated in FIG. 3.

The gas control unit 110 comprises a primary branch 310 comprisingportions or lines 310A-310E and a secondary branch 320. The secondarybranch is a pilot control branch 320 comprising portions or lines320A-320D. The primary branch 310, specifically the portion 310A of theprimary branch 310, is coupled to the gas inlet 111 via an inlet portionor line 305. The flow meter 113 and the flow rate control 115, which maybe separate components or a unitary device, as illustrated in FIG. 3,are disposed within the inlet portion 305. The flow meter 113 displaysthe flow rate of supply gas through the gas inlet 111, and the flow ratecontrol 115 allows a user or operator to modify this flow rate. In anexemplary embodiment, the portions 305, 310A-E, and 320A-D arerespective tubes. As used herein, a user or operator may be the patientreceiving gas or may be a person, such as a medical practitioner, whooperates a gas control unit for benefit of a patient.

The portion 310A couples the primary branch 310 to the inlet portion 305and is coupled to a primary flow inlet 331 of a pilot activated gassparing valve 330 (also referred to herein as “pilot valve 330” or“pneumatic control valve 330”). The gas sparing valve 330 additionallycomprises a primary flow outlet 332 and a pilot control input 333. Thegas sparing valve 330 is normally closed, i.e., when the pressure at thepilot control input 333 is below a threshold pressure required to activethe gas sparing valve 330, the gas sparing valve 330 is closed, and noprimary gas flows from the primary flow inlet 331 to the primary flowoutlet 332.

As described in more detail below, the pilot activated gas sparing valve330 is controlled by the pilot control branch 320 to cause primary gasto flow through the primary flow outlet 332 of the valve 330. Suchoutputted gas flows through a portion 310B of the primary branch 310,through the pop off pressure relief valve 118, through a portion 310C ofthe primary branch 310, through the PIP pressure relief valve 119, andthrough portions 310D-310E of the primary branch 310 to the main gasoutlet 117.

The pilot control branch 320, specifically the portion 320A of the pilotcontrol branch 320, is coupled to the gas inlet 111 via the inletportion 305. The portion 320A connects through a check valve 340 to aportion 320B. The portion 320B is connected to a portion 320C via anelement 341 for pilot flow reduction. In an exemplary embodiment, thevalve 341 is an orifice flow control element. In another exemplaryembodiment, the valve 341 is a needle valve. The portion 320C isconnected to the pilot control port 116.

The pilot control branch 320 is coupled to the control input 333 via aportion 320D of the pilot control branch 320, which portion 320D istapped into the portion 320C. As is discussed in further detail below,the pilot control branch 320 controls the gas sparing valve 330 via thepilot control input 333.

Additional details regarding the disposable breathing circuit 120 areillustrated in FIG. 3 and are now described. The disposable breathingcircuit 120 comprises a main gas line 355 (also referred to herein as a“primary gas line 355”) comprising a first end 121 and a second end 122.The first end 121 of the main gas line 355 is coupled to the main gasoutlet 117 for delivering source gas to the patient. The disposablebreathing circuit 120 further comprises a pilot control line 365comprising a first end 121 and a second end 123. The first end 121 ofthe pilot control line 365 is coupled to the pilot control port 116. Thepilot control line 365 traverses the disposable breathing circuit 120from the first end 121 to the pilot air flow control switch 125 at thesecond end 123. Located at the end 123 of the pilot control line 365 atthe switch 125 is a vent port 351, which vents the end 123 of the pilotcontrol line 365 to atmosphere. It is to be understood that the end 123of the pilot control line 365 and, therefore, the pilot air flow controlswitch 125 may be disposed at any place along the disposable breathingcircuit 120. In an exemplary embodiment, the end 123 of the pilotcontrol line 365 and, therefore, the pilot air flow control switch 125are disposed near the end 122 of the disposable breathing circuit 120for convenience of use by the user activating the device for the patientwearing the mask 130.

As also illustrated in FIG. 3, the second end 122 of the disposablebreathing circuit 120 is coupled to the mask 130 via a mask connection370. In an exemplary embodiment, the mask connection 370 comprises anon-rebreathing element 371 which comprises a flow in/vent outconfiguration 372, which may include one or more exhaust ports to allowfor exhalation by the patient. In an exemplary alternative embodiment,the one or more exhaust ports may be included in the mask 130 itself.

The pilot activated gas sparing valve 330 is controlled by the pressurein the portion 320D at the pilot control input 333 of the gas sparingvalve 330. When the pressure at the pilot control input 333 reaches athreshold pressure, the valve 330 actuates and opens, thereby allowingfull primary gas flow. When the pressure at the pilot control input 333decreases below the threshold activating pressure, the valve 330deactivates and closes, thereby stopping full primary gas flow.

The primary branch 310 and the main gas line 355 together form a maingas circuit 350 for delivering gas to a patient. The pilot controlbranch 320 and the pilot control line 365 together form a pilot controlcircuit 360 for controlling the delivery of gas in the main gas circuit350. By using a main gas circuit 350 and a pilot control circuit 360coupled to the same inlet 111, the same inlet gas flow is used to chargethe main gas circuit 350 and the pilot control circuit 360. It is to beunderstood that description herein of occluding, un-occluding, charging,and venting the pilot control circuit 360 may be referred to asoccluding, un-occluding, charging, and venting portions of the pilotcontrol circuit 360, such as the pilot control branch 320 or the pilotcontrol line, and vice versa.

FIGS. 5A through 5C illustrate alternative exemplary embodiments of thegas port 112, in accordance with an exemplary embodiment of the presentinvention. In a first exemplary embodiment illustrated in FIG. 5A, thepilot control port 116 is separate from the main gas port 117. In asecond exemplary embodiment illustrated in FIG. 5B, the pilot controlport 116 is disposed within the main gas port 117 to provide a unitaryport 112. In a third exemplary embodiment illustrated in FIG. 5C, thepilot control port 116 is disposed adjacent to and in contact with themain gas port 117 to provide a unitary port 112. In such embodiment, theunitary port 112 has a lopsided figure-8 cross section.

Referring now to FIG. 6, there is illustrated an exemplary block diagramof a system, generally designated as 600, which is a simplified versionof the gas sparing circuit 300, in accordance with an exemplaryembodiment of the present invention. The block diagram 600 shows the gassparing circuit 300 in terms of pressures. Further, the block diagram600 in conjunction with FIG. 7A shows how a charged pilot controlcircuit 360 aids in system response. System response is plotted in FIG.7A, which is described below.

In an exemplary embodiment, the pilot valve 330 requires a minimumthreshold pressure P_(C) to actuate and open the valve 330. It is to beunderstood that in any system, for a given circuit size, e.g., the sizeof the pilot control circuit 360, there will be a time value, t, for thefull pressure in the system to build, i.e., for the gas sparing circuit300 to activate, when the system is acted upon or, in the case herein,when the pilot control line 365 (pilot control circuit 360) is occluded.

The time t is affected by the total dead volume in the circuit 360. Thusminimizing the dead volume by controlling the interior diameter of thetubing in the circuit 360, the pliancy in the tubing material, and thelength to the occluding part, e.g., the length from the flow reductionelement 341 to the pilot air flow control switch 125, assists inreducing the time t. To reduce the time t to activation even further, apilot control circuit 360 that not only utilizes the lowest dead volumeavailable but also maintains a pressure as high as possible in the pilotcontrol circuit 360, i.e., as close to the activation pressure of thevalve 330 as possible, allows for almost immediate activation of thevalve 330, thereby reducing the activation time t. Allowing a constant,albeit small, flow in the pilot control circuit 360 allows the gassparing circuit 300 to maintain a pressure in the pilot control circuit360 that is very close to the pressure P_(C). Should the pilot controlcircuit 360 have no initial flow, the time required to equalize to thesystem inlet pressure, once flow is initiated and the circuit 360occluded, would be significantly greater than the subject pilot controlcircuit 360 with constant flow.

Because there is a desire to minimize vented or lost gas in the main gascircuit 350, the flow rate in the pilot control circuit 360 is desirablyminimized. Thus, the gas control unit 110, desirably includes a flowreduction element 341 which causes a small drop in pressure in the pilotcontrol branch 320 to just below the threshold pressure P_(C) of thevalve 330 and which limits the flow rate in the pilot control circuit360 when not occluded. A properly sized flow reduction element 341 inthe pilot branch 320 provides both pressure drop and flow rate controlwhen the pilot control circuit 360 is un-occluded and the gas in thepilot control circuit 360 is allowed to flow. When the pilot controlcircuit 360 is occluded and no flow occurs, i.e., when the pilot airflow control switch 125 occludes the vent port 351, there will be nopressure drop across the flow reduction element 341, and the pressure inthe pilot control circuit 360 will rise quickly, because of theminimized circuit dead volume. The pressure in the pilot control circuit360 equalizes with the pressure at the inlet 111 to actuate the valve330.

In FIG. 6:

P₁=System inlet pressure  (1)

P₂=Pressure just after the flow reduction element 341 at the pilotcontrol input 333 of the gas sparing valve 330  (2)

P₃=Pressure in the pilot control line 365 proximal to the vent port 351and at the end 122 of the main gas line 355  (3)

P_(C)=Pressure at the input 333 required to actuate the valve 330  (4)

For the simplified system 600 of FIG. 6, the following relationshipshold true when the vent port 351 is open:

P₂<P₁  (5)

P₂>P₃,  (6)

P₂<P_(C)≦P₁  (7)

By selecting the flow reduction element 341 and by reducing dead volumeand pliancy (expandability of components) in the pilot control circuit360, the pressure P₂ can be held very close to P_(C), such that uponocclusion of the pilot circuit, P₂ quickly rises to the level of P₁,which is greater than P_(C), and actuates the valve 330.

Pilot control is accomplished by occluding and venting the pilot controlcircuit 360, more specifically the control line 365. FIG. 3 illustratesthat the gas sparing circuit 300 comprises a pilot air flow controlswitch 125. It is to be understood that the gas sparing circuit 300 isnot limited to the element 125 being a switch. Any device to temporarilyocclude the pilot control line 365 to actuate and open the gas sparingvalve 330 is contemplated. The pilot control switch 125 operates in anormally open condition which holds the gas sparing valve 330 closed sothat no gas flow occurs through the main gas branch 310 and the main gasline 355.

Illustrated in FIG. 7A is a graph of the pressures, P₁, P₂, and P₃ inthe system 600, plotted over time as the pilot control circuit 360 isun-occluded, then is occluded, and then re-un-occluded. Illustrated inFIG. 7B is a graph of the main gas flow, designated as V₁, in the maingas line 355 and the pilot gas flow, designated as V₂, in the pilotcontrol line 365, in accordance with an exemplary embodiment of thepresent invention. These graphs are now described with reference tooccluding and un-occluding the pilot control line 365.

As illustrated, when the system 600 is in its initial state in which thepilot control circuit 360 is not occluded, the system inlet pressure P₁remains relatively constant at a pressure P_(A), the pressure in theline 305; pressure P₂ remains relatively constant at a pressure P_(B),the residual, pre-charged pressure in (the original was better) thepilot control circuit 360; and pressure P₃ is constant at a pressureP_(atm), atmospheric pressure, because the vent port 351 is open toatmosphere. Main gas flow V₁ is at 0 because the gas sparing valve 330is closed. Pilot gas flow V₂ in the pilot control line 365 is at V_(P),the un-occluded flow rate.

Pressure P₂ remains relatively constant at a pressure P_(B) because theelement 341 provides for a constant pressure drop from pressure P_(A).As noted above, pressure P_(C), which is illustrated in FIG. 6, is aconstant, as it is the predetermined pressure required to actuate thevalve 330. P_(C) can be adjusted by altering the internal valveactuation spring and/or diaphragm in the valve 330.

Pressures P₂ and P₃ respond to occlusion and then un-occlusion in thepilot control circuit 360 (pilot control line 365). At time t₁, thepilot control circuit 360 is occluded, and pressure P₂ increases as thegas in the pilot control line 365 is no longer vented at the vent port351. Pilot gas flow V₂ quickly reduces to zero because the pilot controlline 365 is occluded. Pressure P₂ increases until equal to P_(C) at timet₂, at which time the valve 330 is actuated and opens to allow theprimary gas to flow through the main gas circuit 350 at the full inletpressure P₁. The pilot gas flow V₁ begins to quickly increase from 0 toV_(M), the un-occluded flow rate, at t₂+Δt, where Δt is a small elapsedtime after t₂. The pressure P₂ continues to increase until it reachesthe inlet pressure P₁ (P_(A)) at time t₃, at which time the pressuredrop across the valve 330 is 0 psi. P₂ remains at P₁ (P_(A)) and V₁remains at V_(m) while the pilot control circuit 360 is occluded.

At time t₄, the pilot control circuit 360 is un-occluded and begins tovent. The pilot gas flow V₂ quickly increases to V_(P). The pressure P₂begins to decrease and continues to do so through time t₅, until itreaches P_(C) at which time the valve 330 deactivates and closes, andthe flow V₁ precipitously decreases to 0. The pressure P₂ continues todecrease until it settles back at its initial pressure P_(B) at time t₆.When vented, the pressure P₂ drops enough to allow the main valve 330 toclose but does not drop to atmospheric pressure P_(atm) due to theresidual constant flow in the pilot control circuit 360 and the lengthof the pilot control circuit 360.

Also illustrated in FIG. 7A is a plot of pressure P₃ at the vent port351 and at the end 122 of the main gas line 355. The plot of P₃ is alsoapproximately similar to the pressure after the flow reduction element341 if the pilot control circuit 360 were held at atmospheric pressure.For purposes of the following discussion, the pressure P₂ just after theflow reduction element 341 in the pilot control circuit 360 when held atatmospheric pressure is designated as P₂′.

The plot of P₃ is now described with the understanding that P₃ isapproximately the same as P₂′. Pressure P₃ is initially at atmosphericpressure, P_(atm). At time 1, the pilot control circuit 360 is occluded,and pressure P₃ increases as the gas in the pilot control line 365 is nolonger vented at the vent port 351. Pressure P₃ increases until equal tothe threshold pressure P_(C) at time t₇, The pressure P₃ continues toincrease until it reaches P₁ (P_(A)) at time t₈. P₃ remains at P₁(P_(A)) while the pilot control circuit 360 is occluded. At time, t₄,the pilot control circuit 360 is un-occluded and begins to vent, and thepressure P₃ begins to decrease and continues to do so through time t₅when the valve 330 deactivates and closes. The pressure P₃ continues todecrease until it settles back at its initial pressure P_(atm).

FIGS. 7A and 7B show that a pilot control circuit 360 which maintains aresidual pressure P_(B) higher than atmospheric pressure P_(atm), willactuate the valve 330 and start the flow V₁ of main gas in the main gascircuit 350 more quickly than a system maintained at P_(atm). Theactuation time for the valve 330 for the system 300, 600 having aresidual pressure P_(B) in the pilot control circuit 360 higher thanatmospheric pressure P_(atm), is t₂−t₁. The time for V₁ to go from 0 toV_(M) is t₂+Δt−t₁. The actuation time for the valve 330 if the system300, 600 were to have a residual pressure P_(atm) in the pilot controlcircuit 360 at the valve 330 would be t₈−t₁. Exemplary values fort₂+Δt−t₁ and t₈−t₁ are 250 ms and 1250 ms, respectively. An exemplaryvalue for Δt is 25 ms. By maintaining the pilot control circuit 360 withpressure P₂ at a residual pressure P_(B) rather than at P_(atm) and byminimizing flow volume (dead volume) in the pilot control circuit 360,the time t₂−t₁ for pressure charging in the pilot control circuit 360and for actuation of the valve 330 is minimized.

As discussed above, the pilot control branch 360 desirably causes quickresponse of the valve 330 to provide almost instantaneous flow to thepatient after activation by the user. The pilot control circuit 360 alsodesirably uses minimal gas flow to actuate the valve 330 circuit andvent minimal gas to the environment when not activated. Conventional gasdelivery circuits allow constant full, high-volume flow to theenvironment even when such gas is not being using by a patient. Suchwaste is not acceptable and is costly. The gas control unit 110 greatlyreduces such waste.

In an exemplary embodiment, the reduced flow and quick response in thepilot control circuit 360 is accomplished by use of a small flow orificein the element 341 to restrict and lower flow rate and volume in thepilot control circuit 360. Further, small bore tubing with minimal wallpliancy is used in the portions 320A-D of the pilot control branch 320and in the pilot control line 365 to allow for a minimal flow area(cross section) and a minimal dead volume to provide for quick actuationof the gas sparing valve 330 when desired.

In addition, allowing a continuous small positive flow in the pilotcontrol circuit 360 at all times minimizes the response time evenfurther since, when occluded while having an initial positive flow, thepilot control circuit 360 is already almost fully charged with gas, asshown in FIG. 7A, and, thus, the internal flow V₂+in the pilot controlcircuit 360 will be almost immediately directed into the gas sparingvalve 330 upon occlusion, thereby building enough back pressure,quickly, to activate the gas sparing valve 330. In an exemplaryembodiment, under such conditions, patient flow V₁ to a patient wearingthe mask 130 is initiated in fewer than 500 milliseconds. In anotherexemplary embodiment, patient flow V₁ is initiated in about 250milliseconds or less.

As shown in FIGS. 7A and 7B, by maintaining the pilot control circuit360 fully charged or nearly fully charged, response time is reducedcompared to conventional systems. Should the pilot control circuit 360be evacuated with no positive pressure or flow, the circuit 360 would beat atmospheric pressure P_(atm) and would require time to fill and fullycharge once flow was applied and the circuit 360 occluded. This chargetime significantly delays system activation and renders use of thesystem 100 not desirable. Since the gas sparing valve 330 requires aminimum threshold pressure P_(C) to activate, the closer the pilotcontrol circuit 360 is maintained to this minimum threshold pressureP_(C), the quicker activation of the valve 330 occurs when the pilotcircuit 330 is occluded and the full pilot pressure P_(A) reached.

Separate gas sources for the main gas circuit 350 and the pilot controlcircuit 360 are not practical in a modular portable system with minimalcomplexity. Thus, the system 300 is designed so that the pilot controlgas, the gas within the pilot control circuit 360, is sourced from thesame place as the system gas (also referred to herein as the “primarygas” or “patient gas”), the gas within the main gas circuit 350 (alsoreferred to herein as the “primary gas circuit 350”).

Because the system 300 uses a common gas source for both the primary andpilot gas flow, means to stop the loss of pilot gas flow and pressureupon activating the gas sparing valve 330, until desired by theoperator, is desirably implemented. Should no means be provided tomaintain the required pressure in the pilot control circuit 360 to holdthe main valve 330 open, the main valve 330 may begin to oscillatebetween an open and closed position as the pressure P₂ in the pilotcontrol branch 320 fluctuates down and then up as the main valve 330opens and then closes, respectively. This may result in gas flow in themain gas line 355 oscillating between flow and no flow in a manner notdesired by the operator.

To reduce or eliminate oscillation of the valve 330, the system 300comprises a check valve 340, which is designed to eliminate backflow inthe pilot branch 320 if there is a shift in the pressure differentialacross the element 341 when the gas sparing valve 330 opens, this shiftin pressure differential would reverse the flow direction of gas in thepilot branch 320. The check valve 340 is used to lock and maintainpressure in the pilot branch 320 once a pressure level has beenestablished assuming no gas is then allowed to escape from the oppositeend of the branch 320, i.e., via the vent port 351. Thus, by placing acheck valve in the pilot control circuit 360 before the flow reductionelement 341, when the outlet switch/valve 125 is occluded by theoperator and the pilot control circuit 360 is pressurized, any drop inpressure on the inlet side of the check valve 340, which may occur uponthe main valve 330 opening, will not cause a pressure drop in the pilotcontrol circuit 360. Thus, the main valve 330 remains open and does notoscillate between open and closed. Without the check valve 340, anyundesired (uncontrolled) loss of pressure in the main gas circuit 350might cause the main valve 330 to close prematurely in an uncontrolledmanner or to oscillate between open and closed due to pressurefluctuations in the pilot control circuit 360. Both premature closing ofthe main valve 330 and uncontrolled oscillation of the main valve 330between open and closed are undesirable.

Referring now to FIGS. 8A and 8B together, there is illustratedoperation of an exemplary embodiment of the pilot air flow controlswitch 125 disposed within a handle 800, in accordance with an exemplaryembodiment of the present invention. FIG. 8A illustrates the switch 125in an open position A. FIG. 8B illustrates the switch 125 in a closedposition B. As illustrated in FIGS. 8A and 8B, the handle 800 isconnected to a second end 122 of an exemplary embodiment of thedisposable breathing circuit 120, generally designated as 120′ in FIGS.8A and 8B. The handle 800 may be permanently or removably attached tothe disposable breathing circuit 120. FIG. 8C illustrates various viewsof an exemplary embodiment of the disposable breathing circuit 120′, inaccordance with an exemplary embodiment of the present invention.

The disposable breathing circuit 120′ illustrated in FIGS. 8A-8C differsfrom the disposable breathing circuit 120 because the disposablebreathing circuit 120′ does not include the switch 125 or the vent 351.Instead, those components are disposed within the handle 800 illustratedin FIGS. 8A and 8B. Thus, the main gas line 355 extends through thedisposable breathing circuit 120′ from the first end 121 to the secondend 122, which second end 122 is connected to a first end 821 of thehandle 800. The pilot gas line 365 extends through the disposablebreathing circuit 120′ from near the first end 121 to near the secondend 122, as seen best in FIG. 8C.

In the embodiment of the handle 800 illustrated in FIGS. 8A and 8B, thepilot air flow control switch 125 is a pliant membrane 810 disposed overa pilot control orifice 820. The switch 125 and specifically the pliantmembrane 810, when in position A, does not occlude the pilot controlorifice 820 and when in position B, does occlude the orifice 820. In analternative embodiment, a rigid flow switch could replace the pliantmember 810 and perform the same function.

The handle 800 allows the user to hold the mask 130 against thepatient's mouth and nose. The handle 800 comprises a bend 830 and an end822 to which the mask 130 is attached. At the second end 123 of thepilot control line 365, the pilot control line 365 comprises a bend 825,which connects the pilot control line 365 to a riser or port 835 whichopens to atmosphere at the pilot control orifice 820.

As illustrated in FIG. 8A, when the pilot air flow control switch 125 isin the open position A, pilot gas 840 flows through the pilot controlline 365, around the bend 825, up the riser or port 835, and through thepilot control orifice 820. The pilot gas 840 then passes through anexhaust port 845 and is exhausted through the vent port 351. Becausepilot gas 840 is vented through the vent port 351, the gas sparing valve330 is deactivated and does not allow main gas 850 to flow through themain gas line 355.

As illustrated in FIG. 8B, when the pilot air flow control switch 125 isin the closed position B, i.e., when the pliant member 810 is depressed,the pilot control orifice 820 is occluded by the membrane 810, and pilotgas 840 is not vented through the vent port 351. The lack of pilot gasflow is labeled as 840′ in FIG. 8B. Because there is no pilot gas flow840′, the gas sparing valve 300 is actuated and main gas 850 flowsthrough the main gas line 355, out the second end 822 of the handle 800,and through the mask 130. Upon release of the pliant member 810, thepilot gas 840 vents, de-actuating and closing the gas sparing valve 330and stopping flow of the main gas 850 to the patient mask 130.

FIGS. 8A-8C illustrate that the pilot control line 365 is extendedthrough the breathing circuit 120′ to the end 122 (or near to the end122) of the breathing circuit 120, and the handle 830 is attached to theend of the breathing circuit 120. It is to be understood that in anexemplary embodiment, the breathing circuit 120 may be modified so thatthe handle 830 is disposed at the end 122 of the breathing circuit 120.

Referring now to FIG. 2, there is illustrated a block diagram of analternative system, generally designated as 200, for delivering gas to apatient via an alternative embodiment of the patient mask 130, generallydesignated in FIG. 2 as 130′, in accordance with an exemplary embodimentof the present invention. The system 200 comprises all of the elementsof the system 100, except for the patient mask 130, but additionallyincludes functionality for a second gas delivery mode, as describedbelow, namely in a continuous positive airway pressure (CPAP) gasdelivery mode where a continuous low pressure, low flow-rate gas isrequired after resuscitation.

The system 200 comprises a gas control unit 210, rather than the gascontrol unit 110. The gas control unit 210 comprises the elements111-119, though used in the system 200 capable of a CPAP gas deliverymode, as is now described. Accordingly, the gas control unit 210additionally comprises a CPAP flow rate control 212 to allow the user toselect a desired CPAP flow rate and a mode-selection switch 214 forselection between the CPAP mode and the gas-sparing resuscitation modeof the system 100.

The mask 130′ used with the system 200 differs from the mask 130 usedwith the system 100. The mask 130′ incorporates a CPAP exhalation port216, which allows the user of the mask 130′ to exhale when the system200 is operating in the CPAP gas delivery mode. The mask 130′ isdescribed in more detail below with respect to FIG. 17.

An exemplary view of the external of the gas control unit 210 isillustrated in FIG. 21, in accordance with an exemplary embodiment ofthe present invention. The various components of the gas control unit210 illustrated in FIG. 2 and described above are mounted to anenclosure 2100 of the gas control unit 210. Attached to the enclosure2100 is a handle 2110 for carrying the gas control unit 210.

Referring now to FIG. 4, there is illustrated a block diagram of a gassparing circuit 400 comprising the gas control unit 210, an embodimentof the disposable breathing circuit 120, generally designated in FIG. 4as 120′, and an alternative embodiment of the patient mask 130′,generally designated in FIG. 4 as 130″, in accordance with an exemplaryembodiment of the present invention. The gas sparing circuit 400 usesall of the components illustrated in FIG. 2 and additional components,as illustrated in FIG. 4. The gas sparing circuit 400 incorporates theprimary branch 310 and the pilot control branch 320 of the gas sparingcircuit 300 in the resuscitation side 410 of the gas sparing circuit400. The gas control unit 210 additionally comprises a CPAP circuit orbranch 430 in a CPAP side 420 of the gas sparing circuit 400. The CPAPcircuit or branch 430 comprises portions or lines 430A-430B. The CPAPcircuit or branch 430 is a continuous flow circuit when in use as thereis no gas sparing control on this side.

The resuscitation side 410 comprises the primary branch 310 and thepilot control branch 320 of the gas sparing circuit 300, which branchesoperate similarly in the gas sparing circuit 400 to those in the gassparing circuit 300. The primary branch 310 and the pilot control branch320, however, are modified slightly for use in the gas sparing circuit.First, the portions 310A and 320A are not directly connected to the flowmeter 113 with flow control 115 via the inlet line 305, as they are inthe gas sparing circuit 300. Instead, the inlet line 305 is directlyconnected to the mode-selection switch 214. Second, the portion 310 e ofthe primary branch 310 in the gas sparing circuit 400, while stilldirectly connected to the main air port 117, is also connected to theportion 430B of the CPAP branch 430. Third, the primary branch 310 mayinclude a check valve 440A in the portion 310B or a check valve 440B inthe portion 310D to further restrict back flow into the resuscitationside 410 when the gas sparing circuit 400 is operating in CPAP mode.

The CPAP branch 430 comprises the portion 430A, which couples themode-selection switch 214 to the CPAP flow control valve 212 as needed.The portion 430B couples the CPAP flow control valve 212 to the portion310E of the primary branch 310. The mode-selection switch 214 is coupledto the flow meter 113 and flow control 115 via a portion 440. Themode-selection switch 214 allows the operator to select for CPAPcontinuous air delivery (CPAP mode) through the primary gas line 355 viathe CPAP branch 430 or to select for pilot-controlled primary gasdelivery (resuscitation mode) through the primary gas line 355 via theresuscitation side 410, and the flow control valve 212 allows theoperator to select the rate of gas flow in the CPAP branch 430.

In an exemplary embodiment, the portion 430B includes a pressure reliefvalve 435A and/or a check valve 435B. The pressure relief valve 435Aprovides venting for overpressure in the CPAP branch 430, and the checkvalve 435B prevents backflow in the CPAP branch 430. In anotherexemplary embodiment, CPAP Branch portion 430B could be connected toMain branch portion 310B allowing the pressure relief valve 118 to bedisposed downstream downstream of the connection with the portion 430B.In such embodiment, the pressure relief valve 118 provides venting foroverpressure in either the CPAP branch 430 or the primary branch 310.

Separate flow control valves in the CPAP branch 430 and the main gasbranch 310 are contemplated. These valves are, respectively, the flowcontrol valves 212 and 115. In an exemplary alternative embodiment, theflow control valve 212 is removed, and the flow control valve 115 isused to regulate the rate of gas flow in the main gas branch 310 and theCPAP branch 430. In another exemplary alternative embodiment, the flowcontrol valve 115 is disposed in the portion 310A downstream of themode-selection switch 214 to control flow in the primary branch 310, andthe flow control valve 212 is disposed in the CPAP branch 430 to controlCPAP flow. In yet another exemplary alternative embodiment, check valves440A and/or 440B are contemplated to stop backflow in the primary branch310. The check valves 435B, 440A, and 440B also prevent cross flowbetween the CPAP branch 430 and the primary branch 310.

The mask 130″ differs from the mask 130′ because the mask 130′ includesthe switch 125 and the vent 351, respectively designated as 125′ and351′ in FIG. 4. It is to be understood that the mask 130″ incorporatesthe CPAP exhalation port 216 used in the mask 130′. This port is openwhen in CPAP mode but is closed when in resuscitation mode. In anexemplary alternative embodiment, the disposable breathing circuit 120and the mask 130′ are used with the gas sparing circuit 400. In anotherexemplary alternative embodiment, the handle 800 may be attached to thedisposable breathing circuit 120′ and the mask 130′ if used with the gassparing circuit 400 or may be incorporated into the mask 130″ if usedwith the gas sparing circuit 400.

Referring now to FIG. 9, there is illustrated an exemplary alternativeembodiment of the gas sparing circuit 300, generally designated in FIG.9 as 900, in accordance with an exemplary embodiment of the presentinvention. The gas sparing circuit 900 uses all of the componentsillustrated in FIG. 3, modified as described below, and additionalcomponents, as illustrated in FIG. 9. The gas sparing circuit 900incorporates the main gas branch 310 and the pilot control branch 320,as modified as a pilot control branch 320′. In another exemplaryembodiment, a CPAP branch, such as the CPAP branch 430 of FIG. 4, couldalso be added to the gas sparing circuit 900 to add CPAP functionality.

The pilot control branch 320′ comprises the elements of the pilotcontrol branch 320 of the pilot control branch 320 and additionally apneumatic timer control 910 configured to control the on-time of themain gas sparing valve 330. The portion 310D of the pilot control branch320 is replaced by portions 320D′ and 920A and 920B. If used to controlthe on-time of the main gas sparing valve 330, the pneumatic timercontrol 910 is a normally open valve.

The portion 320D′ couples an output 992 the pneumatic timer control 910to the control side 333 of the gas sparing valve 330. The portion 920Acouples the portion 320C to an input 911 of the pneumatic timer control910. The portion 920B couples the portion 320C to a timer unit 993.

Operation of the gas sparing circuit 900, with on-time control, is nowdescribed. Operation begins with the pilot control circuit 360 in anun-occluded state, the gas sparing valve 330 closed, and pilot gas atpressure PB is applied to the control side 333 of the gas sparing valve330 through the pneumatic timer control 910, which is in an open state.Upon closure or occlusion of the pilot control line 365, the gas sparingvalve 330 opens, as described above with respect to FIGS. 3, 6, and 7,and pressure at the timer unit 993 increases. When the pressure at thetime unit 993 reaches a threshold pressure, a counter within the timerunit 993 starts and counts until it reaches an activation time. Afterthe activation time of the timer 993 is reached, the timer 993 cyclesand closes a valve in the pneumatic timer 910 and vents the pilotconnection 320D′ of the gas sparing valve 330 via a vent 994, therebycausing the gas sparing value 330 to close and main flow through themain gas line 355 to stop. The cycle may repeat after the pilot controlline 365 is vented, which causes the timer unit 993 to reset. In thismodality, the provision of primary gas through the gas sparing valve 330for each breath is triggered by the user occluding the pilot controlline 365. Thus, re-occlusion of the pilot control line 365 starts eachresuscitation breath. Also, in this modality, the user could deliverinhalation breaths in succession without allowing for completeexhalation, if desired, since any venting of the pilot line would resetthe timer valve 993 and allow the cycle to restart very quickly.Exhalation is accomplished as described herein, such as via exhaustports in the mask 130 or 130′ or via exhaust ports in a hand piece towhich the mask 130 or 130′ is connected, such as the exhaust ports 1226in the hand piece 1200 described below.

In this way, the gas sparing circuit 900 controls the amount of time gasis provided via the main gas line 355 and thereby controls theinhalation time of the patient using the gas sparing circuit 900. Theactivation time can be adjusted from fractions of a second to severalseconds as desired by the user. The user may set the activation (breath)time of the timer unit 993 to be between 0.5 to 3 seconds. Desirablebreath time is approximately 1.0 to 1.5 second for inhalation breathflow followed by 1.0 to 3.0 seconds of vent or exhalation time.

Should the user desire automatic continuous control of the inhalationtime followed by automatic control of the exhalation time, two pneumatictimers could be used in an exemplary embodiment of the gas sparingcircuit 900, generally designated as 1000 in FIG. 10, in accordance withan exemplary embodiment of the present invention. The gas sparingcircuit 1000 uses all of the components illustrated in FIG. 3, modifiedas described below, and additional components, as illustrated in FIG.10. The gas sparing circuit 1000 incorporates the primary branch 310 andthe pilot control branch 320′, as modified as a pilot control branch320″. In another exemplary embodiment, a CPAP branch, such as the CPAPbranch 430 of FIG. 4, could also be added to the gas sparing circuit1000 to add CPAP functionality.

The pilot control branch 320″ comprises the elements of the pilotcontrol branch 320′ of the gas sparing circuit 900 and additionally twopneumatic timer controls 1010 and 1020. In this configuration, the firsttimer control 1010 controls the on (inhalation) time (the time duringwhich the gas sparing valve 330 is open) and the second timer control1020 controls the off (exhalation) time (the time during which the gassparing valve 330 is closed).

In the pilot control branch 320″, the element 341 is coupled to an inlet1011 of the first timer 1010 via a portion 1030A. An outlet 1012 of thefirst timer control 1010 is coupled to an inlet 1021 of the second timercontrol 1020 via portion 1030D. An outlet 1022 of the second timercontrol 1020 is coupled to a timer 1013 of the first timer control 1010via a portion 1030B.

The control side 333 of the gas sparing valve 330 is coupled to theoutlet 1012 and the inlet 1021 via a portion 1030E which also connectsto the outlet port 112. The portion 1030E is also coupled to a timer1023 of the first timer control 1020 via a portion 1030F.

Operation of the gas sparing circuit 1000 is now described. Operationbegins with the pilot control circuit 360 in an un-occluded state, thegas sparing valve 330 closed, and pilot gas at pressure P_(B) is appliedto the control side 333 of the gas sparing valve 330 through thepneumatic timer control 1010, which is in an open state. The pneumatictimer control 1020 is in a closed state, and the line 1030B has beenvented. Upon closure or occlusion of the pilot control line 365, the gassparing valve 330 opens, as described above with respect to FIGS. 3, 6,and 7, and primary gas is provided to the patient via the primarycircuit 350. At the same time, pressure at the timer unit 1023increases. When (almost instantaneously) the pressure at the timer unit1023 reaches a threshold pressure, a valve within the pneumatic timercontrol 1020 closes and a counter within the timer unit 1023 starts.When the counter within the timer unit 1023 reaches an activation time,the timer 1023 cycles a valve in the pneumatic timer control 1020 to anopen state and vents the pilot circuit 360.

Because the valve in the pneumatic timer control 1020 is opened, pilotgas is allowed to pass from the inlet 1021 to the outlet 1022 and to thetimer 1013 of the pneumatic timer control 1010 via the line 1030B.Pressure at the timer unit 1013 increases. When (almost instantaneously)the pressure at the timer unit 1013 reaches a threshold pressure, avalve within the pneumatic timer control 1010 closes, thereby shuttingdown flow of the pilot gas from the inlet 1011 to the outlet 1012 of thepneumatic timer control 1010. Because the pneumatic timer control 1020is in an open state and is venting the pilot circuit 360, the gassparing valve 330 closes. This stops the flow of gas to the patient andallows exhalation to occur. This discontinuation of pilot flow alsoresets timer 1020.

A counter within the timer unit 1013 starts and counts until it reachesan activation time. After the activation time of the timer 1013 isreached, the timer 1013 cycles the valve in the pneumatic timer 1010 toan open state to restart the flow of pilot gas from the inlet 1011 tothe outlet 1012, which applies pilot gas to the pneumatic timer control1020 to close the valve therein. At the same time, the gas sparing valve330 opens, and primary gas is again provided to the patient via theprimary circuit 350. Once the exhalation cycle is started, i.e. when thevalve in the pneumatic timer 1010 closes, the user cannot deliveranother inhalation breath until the exhalation cycle is fully completed.This ensures a full exhalation cycle is completed.

Operation of the gas sparing circuit 1000 cycles through theabove-described process as long at the pilot air flow control switch 125is closed. When the user releases the switch 125, the cycle stops.Additionally a mechanical or electrical latch or closure device can beadded to the gas sparing circuit 1000, at the pilot control switch 125,that would allow for mechanical latching (closure) of the switch 125 inthe closed position thus allowing for continued ventilation of thepatient where the user would not have to hold the switch 125 in theclosed position with his or her hand. This latch could be switched inand out to hold the pilot control switch 125 in the closed position orallow it to be in the open position for manual, finger-based activation.

In this configuration, once the pilot control line 365 is occluded, thesystem 1000 automatically cycles between inhalation (gas sparing valve330 open to provide gas in the main gas line 355), and exhalation (gassparing valve 330 closed). The user may set the ventilation breath timeby setting the activation time of the timer unit 1023 to be between 0.5to 3 seconds. Desirable breath time is approximately 1.0 to 1.5 secondfor inhalation breath flow. The user may set the exhalation time bysetting the activation time of the timer unit 1013. Desirable exhalationtime is approximately 1.0 to 3.0 seconds for exhalation breath flow.

Although FIGS. 9 and 10 illustrate using pneumatic time controls, otherembodiments using electro-pneumatic controls or timer-based triggers arecontemplated. In a gas-sparing circuit incorporating a timer-basedtrigger, the user activates the trigger to occlude the pilot controlline 365 and activate the gas sparing valve 330. Then, within thetrigger, a mechanical, electrical, or pneumatic-mechanical switch cyclesover the desired time period and opens the pilot control line 365 toatmosphere, thereby closing the gas sparing valve 330, stopping primaryairflow.

Referring now to FIG. 11A, there is illustrated a side cross-sectionalview of an exemplary embodiment of a pneumatic-mechanical timer-basedtrigger 125′ and to FIG. 11B, there is illustrated a top view revealinginternal details of the trigger 125′, in accordance with an exemplaryembodiment of the present invention. The trigger 125′ may be substitutedinto the gas sparing circuits 300 and 400 to replace the trigger 125.

The trigger 125′ comprises a housing 1101 in which a trigger handle 1102is slidably disposed. The trigger handle 1102 is connected to a guiderod 1107 which passes through slots 1103 and 1104 in the housing. Theguide rode 1107 may slide from one end of the slots 1103 and 1104 to theother as the trigger handle 1102 slides within the housing 1101. Thetrigger handle 1102 is coupled to a plunger which terminates in a softdiaphragm 1106. Disposed on the plunger between the trigger handle 1102and the diaphragm 1106 is a spring 1114.

The pilot control line 365 pierces a first end 1121 of the housing 1101and terminates within an interior space 1120 of the housing 1101 formedbetween the housing 1101 and the diaphragm 1106. The interior space 1120vents to the outside of the housing 1101 via vents 1111. Disposed at asecond end 1131 of the housing 1101 is a plunger 1130, which is attachedto the trigger handle 1102. The housing 1101 forms an interior space1140 between the plunger 1130 and the second end 1131 of the housing1101. The interior space 1140 vents to the outside of the housing 1101via a one-way diaphragm valve 1112. Also disposed in the housing 1101 atthe second end 1131 is a vent valve 1113, which is used to set venttime.

Disposed on the housing of the housing 1101 is a timer adjuster nut 1108for adjusting the timer. Disposed around the housing 1101 between thenut 1108 and the trigger handle 1102 is a spring 1110. A stop 1109provides a stop for lateral movement of the trigger handle 1102.

Operation of the trigger 125′ is now described. The user pulls thetrigger 125′ toward the first end 1121, thereby pushing the softdiaphragm 1106 against the end of the pilot control line 365 andcompressing the spring 1114 between the diaphragm 1106 and the triggerhandle 1102. The spring 1114 provides for tactile feeling in the trigger125′. Once the pilot control line 365 is occluded, the gas sparing valve330 opens allowing primary flow.

When the trigger handle 1102 is pulled, in addition to advancing thesoft diaphragm 1106, the trigger handle 1102 pulls the plunger 1130 awayfrom the second end of the housing 1101. As the trigger handle 1102 andplunger 1130 advance, the chamber fills 1140 with air via the one waydiaphragm valve 1112. When the trigger handle 1102 is released either bythe user or by design via an automatically disengaging triggeractivator, the spring 1110 applies force on the trigger handle 1102 tomove the plunger 1130 back to its initial position. Since the chamber1140 is now filled with air, the pressure in the chamber 1140 resistsmovement of the plunger 1130. Air from the chamber 1140 vents withmovement of the plunger 1130. The adjustable vent valve 1113 allows therate of the venting of the chamber 1140 to be controlled.

As the air in the chamber 1140 vents through the vent valve 1113, theplunger 1105 moves toward its original position and the pressure of thespring 1114 on the soft diaphragm 1106 begins to reduce. When theplunger 1105 has travelled a sufficient distance, the force of thespring 1114 on the diaphragm 1106 will be low enough such that thepressure in the pilot control line 365, which is 50 psi, will createenough force on the rear surface of the soft diaphragm 1106 to force thediaphragm 1106 open. The pilot control line 365 vents through thechamber 1120 and the vents 1111 to the outside of the housing 1101. Asthe pressure in the pilot control line 365 reduces past pressure PC, thegas sparing valve 330 closes and air flow in the main gas line 355stops. The spring 1110 pushes the trigger handle 1102 laterally untilthe trigger handle 1102 comes into contact with the stop 1109, at whichtime the plunger 1130 stops moving.

Thus, a timer circuit is created by the timer-based trigger 125′. Thetime duration of air flow through the main gas line 355 is controlled bythe return travel distance of the trigger handle 1102 and the speed ofthe plunger 1130. Adjustment of the nut 1108 adjusts travel of thetrigger handle 1102 to allow adjustment of the timer circuit of thetimer-based trigger 125′. Further, the vent time of the chamber 1140 isadjustable by the vent valve 1113 to further provide for adjustment ofthe timer circuit of the timer-based trigger 125′.

A patient using the CPAP system 200 may attempt to breathe in an amountof air that is larger than baseline air flow provided by the CPAP side420 of the system 200. Under these conditions, a means is desirablyprovided to allow for this larger air quantity to enter the system 200.

In conventional CPAP systems, the masks have special valves that allowfor this larger air quantity. Although use of a special mask is possiblein the CPAP system 200, it is not optimal. In addition, if spontaneousbreathing were to occur during normal resuscitation where a CPAP mask ina conventional CPAP system cannot be used, the patient would not be ableto draw in the extra air desired.

In conventional bag and mask systems, a valve within the rear of the bagsystem allows for air flow should the patient begin to breathe. However,these devices cannot provide CPAP functionality, and they have no flowand pressure controls. In the system 200 or 400 described above, becausesuch systems are closed or could be very remote from the patient, avalve in the system that would allow for spontaneous breathing would beineffective because the breathing circuit 120 would be too long to allowfor minimal flow restriction. Thus, in order to minimize the restrictionto a spontaneous breath with the system 200 or 400, it is desirable toprovide a spontaneous breath valve system as close to the patient aspossible. However, this valve desirably remains closed duringresuscitation and CPAP positive air flow and only opens when an airflow, larger than the resuscitation or CPAP flow, is demanded by thepatient via inhalation breath volume.

Referring now to FIG. 12, there is illustrated an exemplary embodimentof the mask connection 370, generally designated as 1200 in FIG. 12, inuse with a valve system 1250 to accommodate a patient's ability to drawin extra air if desired, in accordance with an exemplary embodiment ofthe present invention. The mask connection 1200 comprises a housing1210, a rotating outlet port 1220, and the valve system 1250. Thehousing 1210 comprises, at a first end 1212, a gas inlet 1211, which isconnected to the second end 122 of the disposable breathing circuit 120,and, at a second end 1220, an outlet 1222, which is connected to themask 130. In an exemplary embodiment, the housing 1210 is a two-piecehousing comprising a first portion 1210A and a second portion 1210B. Thevalve system 1250 allows the same mask 130 (illustrated in FIGS. 3-4) tobe used for either respiration or CPAP and allows for spontaneousbreathing along with the traditional non-rebreathing function.

The valve system 1250 comprises a unidirectional valve 1260 and atwo-way valve diaphragm 1270 comprising a duck bill valve 1272, and adiaphragm 1275 connected to the duck bill valve 1272. In the exemplaryembodiment illustrated in FIG. 12, the duck bill valve 1272 and thediaphragm 1275 are a flexible unitary structure. It is to be understoodthat other embodiments in which the duck bill valve 1272 is separatefrom the diaphragm 1275 are contemplated.

The unidirectional valve 1260 is in a normally closed state in which itseals breath ports 1265 in the housing 1210. Disposed inside of thehousing 1210 around the unidirectional valve 1260 is a seal ring 1264,which is configured to provide a seal against the two-way valvediaphragm 1270 during patient exhalation. A view of an alternativeembodiment of the unidirectional valve 1260 is illustrated in FIG. 12A.

The rotating outlet port 1220 is rotatably attached to the housing 1210.The outlet port 1220 is configured to rotate relative to the housing1210 to provide for patient comfort during use. A portion of therotation outlet port 1220 adjacent to the two-way valve diaphragm 1270is a seal rim 1224 which is configured to seal against the two-way valvediaphragm 1270 during patient inhalation.

Disposed in the housing adjacent the rotating outlet port 1220 areexhaust ports 1226 and an exhaust seal 1228 for allowing one-wayoperation of the exhaust ports 1226. In an exemplary embodiment, theexhaust ports 1226 and the exhaust seal 1228 are disposed in the secondportion 1210B of the housing 1210.

Operation of the mask connection 1200 is now described. In the maskconnection 1200, when air flows into the inlet 1211 in the resuscitationor CPAP mode, it flows through the two-way inlet valve diaphragm 1270,via the duck bill valve 1272, which opens under positive inhalation airflow, to the outlet 1222. This air also forces the diaphragm 1275 ofthis valve diaphragm 1270 against the seal rim 1224.

Air flows to the mask 130 during gas delivery or when the patientinhales. During patient exhalation, the Duck bill portion 1272 of thetwo-way valve diaphragm 1270 closes and the exhaled air forces thediaphragm portion 1275 off the seal 1224 and against the seal rim 1264.The outlet 1222 is thereby sealed from the interior space 1211 of thehousing 1210. So sealed, the outlet 1222 directs the patient's exhaledair in from the outlet 1222 around the seal rim 1224 and through theexhaust ports 1226 and past the exhaust seal 1228. The exhaust seal 1228is a one-way exhaust seal that serves as a backup for the diaphragm sealring 1224 during inhalation to ensure that no air can reverse flow intothe exhaust ports 1228.

The unidirectional valve 1260 allows for the patient to breathespontaneously. Should the patient spontaneously breathe or inhale avolume that is higher than that being delivered at the inlet 1211 of themask connection 1200, the spontaneous breath valve 1260 opens and allowsadditional air to flow to the patient through the spontaneous breathports 1265. This valve 1260 only stay opens if the volume demanded atthe output 1222 is higher than the volume at the inlet 1211, i.e., anegative pressure at the inlet 1212 is developed. As soon as the volumedemanded at the output 1222 drops below the volume provided at the inlet1212, the valve 1260 closes and seals the spontaneous breath ports 1265.Thus, the spontaneous breath valve 1265 remains closed during all gasinlet 1212 function unless the patient creates an excess demand. Becausethe valve system 1250 is proximal to the patient, minimal restriction toairflow is created. This restriction is designed to be no more than5cmH₂O in negative pressure. Thus, a single valve assembly 1250breathing circuit can be used for both direct resuscitation and for CPAPwherein spontaneous breathing could occur.

Illustrated in FIG. 12B are exemplary side and top views of the maskconnection 1200 attached the second end 122 of the disposable breathingcircuit 120′, in accordance with an exemplary embodiment of the presentinvention. The pilot control line 365 is shown unconnected at the firstand second ends 121 and 122. It is to be understood that the pilotcontrol line 365 at the first end 121 of the disposable breathingcircuit 120′ may be connected to the pilot control port 116 of thesystem 100, and the second end 122 of the disposable breathing circuit120′ may be connected to a pilot connection point on a mask or maskconnection, as described herein. FIG. 12B illustrates a closercross-sectional view of the first end 121 of the disposable breathingcircuit 120′.

Referring now to FIG. 13, there is illustrated a hand piece, generallydesignated as 1300, in accordance with an exemplary embodiment of thepresent invention. The hand piece 1300 may be used in cooperation with aconventional mask or the mask of FIG. 17 described below.

The hand piece 1300 comprises a flexible frame 1310 which is configuredto fit over a conventional resuscitation mask. The hand piece includes ahole 1320 through which the connection port of the conventional maskpasses. Positioned at a first end 1301 of the hand piece 1300 is a pilotcontrol switch 1340 coupled to a vent 1344 for venting a pilot circuit,such as the pilot circuit 360. The switch 1340 and vent 1344 functionsimilarly to the switch 125 and vent 315 illustrated in FIGS. 8A and 8B.A flexible elastomeric switch cap 1342 is placed over the switch 1340for operating the switch 1340.

The switch 1340 is coupled to a pilot control line extension tube 1330at a first end 1331 of the tube 1330. Coupled to a second end 1332 ofthe tube 1330 is a connector 1335 for connecting the tube 1330 to otherportions of the pilot control circuit 360.

A system 1400 in which the hand piece 1300 may be used is illustrated inFIG. 14, in accordance with an exemplary embodiment of the presentinvention. The system 1400 comprises the disposable breathing circuit120′, an adapter 1401 connected to the end 122 of the disposablebreathing circuit 120′, an optional capnometer 1410 coupled to theadapter 1401, and mask connection 1200 coupled to the capnometer 1410.The mask 130 is connected to the mask connection 1200 via the connectionport 131.

The adapter 1401 comprises a positive end-expiratory pressure (PEEP)control 1402 for regulating PEEP through the adapter 1401. The adapter1401 further comprises a pilot control line 1404 that outputs via anoutput connection 1406 connected to the luer 1335 and a main gas line1408 that is connected to the main gas line 355 of the disposablebreathing circuit 120′.

As illustrated in FIG. 14, the hand piece 1300 is configured to fit overthe mask 130. The hole 1320 of the hand piece 1300 is sized toaccommodate the connection port 131 of the mask 130. Activation of airflow through the mask 130 is achieved by depressing the elastomericswitch cap 1342 which actuates the switch 1340 to occlude the pilotcontrol circuit 360, which in the embodiment illustrated in FIG. 14includes the pilot control line 365, the pilot control line 1404 and thepilot control line extension tube 1330. The gas sparing valve 330 isthereby opened.

An enlarged view of the pilot control switch 1340 is shown in FIG. 13A,in accordance with an exemplary embodiment of the present invention. Theswitch 1340 is constructed similarly to the switch 125 illustrated inFIGS. 8A and 8B and operates similarly.

As seen in FIG. 13A, the switch 1340 is formed by the elastomericmembrane 1342 which is attached to the frame 1310 of the hand piece 1300over a chamber 1348. The end 1331 of pilot control line 1330 is disposedwithin the frame 1310 and opens to the chamber 1348 at an opening 1349.A seal ridge 1346 is disposed around the opening 1349 of the pilotcontrol line 1330.

When the elastomeric membrane 1342 is in the state shown in FIG. 13A,i.e., when it is in a non-depressed state, pilot gas passes through thepilot control line 1330, out the opening 1349, through the air chamber1348, and out the vent port 1344. Under this condition, the gas sparingvalve 330 is not activated and there is no flow in the primary gascircuit 305. When the elastomeric switch element 1342 is depressedagainst the seal ridge 1346, the pilot gas air flows out the vent 1344is occluded, thereby activating the gas sparing valve 330 and allowingprimary gas to flow through the primary gas circuit 350 until theelastomeric switch element 1342 is released.

In addition to the hand piece 1300 described above, a simple hand piecethat could be used without a mask, and used with other resuscitationapparatus such as an endotracheal tube, is contemplated. Illustrated inFIG. 15 is an endotracheal tube hand piece (also referred to herein as“endotracheal tube adapter”) 1500, in accordance with an exemplaryembodiment of the present invention. The endotracheal hand piece 1500 isconfigured to be used with the disposable breathing circuit 120′. Thedisposable breathing circuit 120′ differs from the disposable breathingcircuit 120 in that the disposable breathing circuit 120′ does notinclude the pilot control switch 125 or the vent 351. Instead, the pilotcontrol line 365 extends through the entire length of the disposablebreathing circuit 120′ to the second end 122. The end 122 of thedisposable breathing circuit 120′ comprises an outlet 1510 of the pilotcontrol line 365 and an outlet 1520 of the main gas line 355.

The endotracheal hand piece 1500 comprises a first end 1501 comprisingan inlet port 1530 and an inlet port 1540. The port 1540 is configuredto receive the outlet port 1510 of the pilot control line 365. The port1540 is coupled to the pilot control switch 1340 and the vent 1344. Theport 1530 is configured to receive the outlet port 1520 of the main gasline 355. The port 1530 communicates with an endotracheal tubeconnection 1550 at a second end 1502 of the endotracheal hand piece1500. The switch 1340 is operated as described above to control the maingas line 355. When operated, the switch 1340 actuates the gas sparingvalve 330 to provide primary gas through the main gas line 355, to theport 1530, and to an endotracheal tube 1560 connected to the connection1550.

Alternative exemplary embodiments of the hand piece 1300 are illustratedin FIGS. 16A and 16B, in accordance with an exemplary embodiment of thepresent invention. Illustrated in FIG. 16A is a hand piece 1600A, whichis, generally, a combination of the hand piece 1300 and the maskconnection 1200, in accordance with an exemplary embodiment of thepresent invention. The hand piece 1600A comprises a handle 1610, a bodyportion 1630, and a mask 1640. The mask 1640 may be rotatably connectedto the body portion 1630. The body portion 1630 is connected to thehandle 1610 by a pliant section 1620, which allows for the handle 1610to bend relative to the body portion 1630.

The disposable breathing circuit 120′ is connected to the hand piece1600A via a rotatable coupling 1640. The rotatable coupling 1640 allowsfor the position of the disposable breathing circuit 120′ to bepositioned for patient comfort when the mask is installed on thepatient. Activation of the gas sparing system is by way of theelastomeric element 1340. It is to be understood that the hand piece1600A may be used in any of the systems for delivering gas to a patientand gas sparing circuits described herein.

Illustrated in FIG. 16B is a hand piece 1600B, which is also, generally,a combination of the hand piece 1300 and the mask connection 1200, inaccordance with an exemplary embodiment of the present invention. Thehand piece 1600B comprises all of the elements of the hand piece 1600A,with a few modifications. The hand piece 1600B comprises an L-shapedhandle 1610′ rather than the mostly vertical handle 1610 of the handpiece 1600A. In one embodiment, the disposable breathing circuit 120′may be connected to the rotating body portion 1630 of the hand piece1600B. In another embodiment, an end 1611 of the handle 1610′ isconfigured to receive the end 122 of the disposable breathing circuit120′.

Referring now to FIG. 17, there is illustrated an exemplary embodimentof the patient mask 130′, in accordance with an exemplary embodiment ofthe present invention. The patient mask 130′ is used with a gas sparingcircuit, such as the gas sparing circuit 400 of the gas delivery system400, in which both resuscitation and CPAP gas delivery modes aredesired. The mask 130′ comprises the CPAP port 216 described above withrespect to FIG. 2. FIG. 17 illustrates the CPAP port 216 in furtherdetail.

The CPAP port 216 comprises a vent port 1700 comprising valve housing1702 integrated with the mask 130′. The valve housing 1702 is capped bya removable cap 1704, which is tethered to the housing 1702 by a lanyard1708. Disposed within the valve housing 1702 is a one-way valve 1706.When the mask 130′ is used with the system 200, and the system 200 isoperating in resuscitation mode, the cap 1704 is placed over the port1700 to not allow resuscitation gas to bypass the patient and exit themask 130′. When operating in CPAP mode, the cap 1704 is removed to allowexhalation breath.

In the case that the mask 130′ is used with the mask connection 1200,exhalation through the ports 1226 is not possible as the diaphragm 1275is in the open position in the CPAP mode. Thus, a second exhalation portis provided via the exhalation port in the mask in FIG. 17. Thus, thevent port 1700 allows for an exhalation breath along with inlet gas flowexhaust for pressure relief within the mask 130′ during CPAP mode sothat the pressure within the mask 130′ during use is maintained at acontrolled level.

FIG. 18 illustrates another embodiment of a system, generally designatedas 1800, comprising the disposable breathing circuit 120′, the maskconnection 1200, the mask 130, and the hand piece 1300, in accordancewith an exemplary embodiment of the present invention. The connector1335 of the hand piece 1300 is connected to the second end 122 of thepilot control line 365 of the disposable breathing circuit 120′. Thefirst end 1212 of the mask connection 1200 is connected to the secondend 122 of the main gas line 355 of the disposable breathing circuit120′, and the second end 1222 of the mask connection 1200 is connectedto the connection port 131 of the patient mask 130. Activation of airflow through the mask 130 is achieved by depressing the elastomericswitch cap 1342 (Should this be 1340) which actuates the switch 1340 toocclude the pilot control circuit 360, which in the embodimentillustrated in FIG. 18 includes the pilot control line 365 and the pilotcontrol line extension tube 1330. The gas sparing valve 330 is therebyopened. Although FIG. 18 illustrates using the mask 130 in the system1800, it is to be understood that the mask 130′ may be also used.

FIG. 19 illustrates an exemplary alternative embodiment of the handpiece of FIG. 13, generally designated as 1900 in FIG. 19, in accordancewith an exemplary embodiment of the present invention. The hand piece1900 includes all of the components of the hand piece 1300, but theframe 1310 is modified as a frame 1310′ having a smaller profile.

FIGS. 20A-20C illustrate various views of yet another alternativeembodiment of the hand piece of FIG. 13, generally designated as 2000 inFIGS. 20A-C, in accordance with an exemplary embodiment of the presentinvention. The hand piece 2000 includes all of the components of thehand piece 1300, but the frame 1310 is modified as a frame 1310″ havinga smaller profile.

Referring now to FIGS. 22A through 22C, there are illustrated,respectively, front, side, and perspective views of an alternativeembodiment of the patient mask 130′, generally designated in FIGS.22A-22C as 130″, in accordance with an exemplary embodiment of thepresent invention. The patient mask 130″ is similar to the patient mask130′, particularly in that it includes the CPAP vent port 1700. Thepatient mask 130″ differs, however, in that it further includes thepilot control switch 1340, which is disposed on the patient mask 130″ inthe embodiment illustrated, rather than on a hand piece. FIGS. 23Athrough 23F illustrate various views of various components of acombination of the patient mask 130″ connected to the mask connection1200, which is connected to the disposable breathing circuit 120′, inaccordance with an exemplary embodiment of the present invention.

Referring now to FIG. 24, there is illustrated an exemplary alternativeembodiment of the gas sparing circuit 300, generally designated in FIG.24 as 2400, in accordance with an exemplary embodiment of the presentinvention. In this gas sparing circuit 2400, the manual pneumatic pilotcontrol line 365 of the breathing circuit 120 or 120′ is replaced by anelectrical switch-activated pilot control line 2465, and the mechanicalpilot control switch 125 is replaced by an electric switch 2425, asshown in FIG. 24. The electrical switch 2425 is placed under a pliantcap 1340 on the mask 130″. The gas sparing circuit 2400 uses all thecomponents illustrated in FIG. 3, modified as described below, andadditional components as illustrated in FIG. 24. For example, the gassparing circuit 2400 incorporates the main gas branch 310 and the pilotcontrol branch 320, as modified to include an electrical pilot controlbranch 2420 and an electrical pilot control line 2465. In anotherexemplary embodiment, a CPAP branch, such as the CPAP branch 430 of FIG.4, could also be added to the gas sparing circuit 2400 to add CPAPfunctionality.

The electrical pilot control branch 2420 of the gas sparing circuit 2400is an electronic control circuit which comprises an electric solenoidvalve 2410 configured to control the gas flow to the main gas sparingvalve 330. The electrically controlled solenoid 2410 is a normally openvalve that allows pilot gas to vent to the atmosphere through a ventport 2414. The pilot input 320C is coupled to the valve 2410 at an inlet2411. The outlet 2412 of the valve 2410 is coupled to the portion 320Dof the pilot control branch 320.

The valve 2410 operation is controlled electrically through the pilotcontrol circuit 360, specifically the electrical pilot control branch2420, the electrical pilot control line 2465, and the switch 2425. Theelectrical pilot control branch 2420 comprises wires 2422 and anoptional timer circuit 2423, and the electrical pilot control line 2465is formed from wires. The optional timer circuit 2423 functions tocontrol the on time and off time of the valve 2410 and, therefore, theon and off time of the gas sparing valve 330, thereby providing forcontinued cycling of the gas sparing valve 330 when activated. The pilotcontrol line 2465 replaces the pilot control line 365 of FIG. 3. Thepilot control line 2465 couples to the connector 112 at a connection(input) 2416, thereby creating a complete electrical circuit with theelectrical pilot control branch 2420.

Operation of the gas sparing circuit 2400, with electronic solenoidcontrol, is now described. Operation begins with the solenoid valve 2410in the normally closed state which allows pilot branch 1420 to be in theoccluded state. In this condition the pilot gas does not flow past thesolenoid valve 2410 into the pilot control line 320D. The gas sparingvalve 330 remains closed as the pilot line 320D on the gas sparing valvecontrol side is vented to atmosphere, P_(atm). Upon closure ofelectrical switch 2425, by depression of the pliant switch cap 1340 onthe mask 130″, an electrical signal is sent through the wires 2465 and2422, and the solenoid valve 2410 is activated. Pilot gas flow isdirected into pilot line 320D. Pilot gas at pressure PB is applied tothe control side 333 of the gas sparing valve 330, and the valve 330opens allowing gas to flow into the main gas side 310, as describedabove with respect to FIGS. 3, 6, and 7. The solenoid valve 2410 remainsactivated, and main gas continues to flow until the switch 2425 isreleased and the signal to the solenoid valve 2410 is deactivated. Upondeactivation of the solenoid valve 2410, the pilot gas in the circuit2460 is occluded, and pilot gas in the line 320D is vented to atmospherethrough the vent port 2414. Pressure in the control side 333 of the gassparing valve 330 drops to P_(atm), and the gas sparing valve 330closes, thereby stopping main gas flow through the circuit 310. Thisoperation can is repeated manually for each desired breath by depressingthe pliant mask switch cap 1340.

In an alternative exemplary embodiment of the gas sparing circuit 2400,there is an optional timer circuit 2423 that will allow for cycling ofthe electrically controlled solenoid valve 2410 for the auto breathfunction with settable on and off times for resuscitation. In thisconfiguration and any of the timer configurations described herein, themask switch 2425 could have a hold-closed latch to allow for the autobreath function to continue after latching the switch closed so the userdoes not have to hold the switch in place.

It is to be understood that the gas sparing circuit 2400 may be modifiedas described herein to provide for CPAP functionality as shown in FIG. 4and/or to include an internal gas supply.

FIG. 25 illustrates a block diagram for yet another exemplary embodimentof a gas sparing circuit, generally designated as 2500, in accordancewith an exemplary embodiment of the present invention. The gas sparingvalve 2530 in this embodiment is an electrically activated solenoidvalve 2530 which is controlled through a mask switch, such as the maskswitch 2425. In this embodiment, in addition to the external gas inlet111, there may be an internal air generation-supply module 2510, whichcan create the desired gas pressure and flow on demand to an outlet2503. A selector valve 2520 is used to select the appropriate gas sourcefrom the inlet 111 or the internal air generation-supply module 2510.

Operation of the electrically controlled main gas solenoid valve 2530 iscontrolled electrically through the electrical pilot control circuit2460. The solenoid valve 2530 is connected through the wires 2422 of theelectrical pilot control branch 2420 to an external electrical pilotcontrol line, e.g., the electrical pilot control line 2465, and to aswitch, e.g., the switch 2425. In an exemplary alternative embodiment,the electrical pilot control branch include the optional timer circuit2423 that functions to control the on time and off time of the valve2530 and, therefore, the on and off time of the main gas flow to thepatient.

Operation of the gas circuit 2500, with electronic solenoid control, isnow described. Operation begins with the solenoid valve 2530 in thenormally closed state which does not allow main gas flow through themain gas circuit 350. Upon closure of the electrical switch 2425 bydepression of the pliant switch cap 1340 in the mask 130″, an electricalsignal is sent through the wires 2465 and 2422, and the solenoid valve2530 is activated. Main gas flow is directed through the main gas branch310. The solenoid valve 2530 remains activated and main gas continues toflow until the switch 2425 is released, at which time the signal to thesolenoid valve 2530 is deactivated. Upon deactivation of the solenoidvalve 2530, main gas flow stops. This operation can is repeated manuallyfor each desired breath by depressing the pliant mask switch cap 1340.

In addition there is an optional timer circuit 2423 that will allow forcycling of the electrically controlled solenoid valve 2530 for the autobreath function with settable on and off times for resuscitation. Inthis configuration and any of the timer configurations described herein,the mask switch 2425 could have a hold closed latch to allow for theauto breath function to continue after latching the switch closed so theuser does not have to hold the switch in place.

It is to be understood that the gas sparing circuit 2500 may be modifiedas described herein to provide for CPAP functionality as shown in FIG. 4and/or to include an internal gas supply 2510, i.e., the internal supply2510 is optional. Also, it is contemplated that the gas sparing circuit2500 can be applied directly to either the internal gas supply 2510 oran external gas supply via the inlet 111 to provide a time controlledbreath pulse through the outlet 2503 to the main gas side 310 and thusto the patient through the port 117.

FIG. 26A illustrates and describes a block diagram for still anotherexemplary embodiment of a gas sparing circuit, generally designated as2600, in accordance with an exemplary embodiment of the presentinvention. This gas sparing circuit 2600 includes both pneumatic manualpilot control functionality and automatic electronic-based auto breathcontrol that is activated by way of a pneumatic valve/switch actuator2603 disposed in the gas line portion 320C. The pneumatic valve/switchactuator 2603 includes a toggle 2603A for toggling between manual andautomatic positions. When the pneumatic valve/switch actuator 2603 isswitched to the automatic position, the gas sparing circuit 2600 cycleselectro-pneumatically in an automatic manner until the switch 2603 isset back to the manual position or gas pressure is removed from thepilot line. This gas sparing circuit 2600 includes both the manual pilotcontrol functionality of FIG. 3 (the manual pneumatic pilot control line365 and the mechanical pilot air flow control switch 125) and theelectrical switch-activated pilot control of FIG. 24 (the solenoid valve2410 and electrical pilot control branch 2420 with the electronic timercircuit 2423) for auto breath capability. The solenoid valve 2410 isdisposed in the portion 320D connected to the control side 333 of thegas sparing valve 330.

Operation of the gas circuit 2600, with manual pilot control andelectrical switch-activated pilot control for auto breath capability, isnow described. Operation of the gas sparing circuit 2600 is identical inoperation to FIG. 3 when the pneumatic valve/switch actuator 2603 is inthe manual gas control position for utilization of the pilot controlcircuit 320, specifically the pilot control line 365 and flow controlswitch 125. In this configuration the electronically controlled solenoidvalve 2410 is in a normally open configuration when no control signal isprovided and pilot gas can pass through the solenoid valve 2410 freely.

When the pneumatic valve/switch actuator 2603A is set in the manualposition, pilot gas flows through the pilot control line 320C. When thepilot control line 365 is occluded by use of the flow control switch125, the pilot circuit 320C becomes occluded, thereby allowing pilot gasto flow through the solenoid valve 2410 and the control line 320D. Pilotgas at pressure PB is applied to the control side 333 of the gas sparingvalve 330, and the valve 330 opens, thereby allowing gas to flow intothe main gas branch 310, as described above with respect to FIGS. 3, 6,and 7. Releasing the mask switch 125 causes the pressure to drop in thepilot line 320D and at control side 333 of the gas sparing valve 330,and the valve 330 closes, thereby stopping gas flow into the main gasbranch 310, as described above with respect to FIGS. 3, 6, and 7.

When the pneumatic valve/switch actuator 2603 is set in the auto breathposition, a toggle 2613A electrically connected to the electronic timercircuit 2423 is closed, and the electronic time circuit 2423 isenergized. Additionally, gas is directed to the pilot line 320D and thecontrol side 333 of the gas sparing valve 330, which opens to allow gasflow through the main gas side 310. At this time, the electronic timercircuit 2423 begins to cycle the electronic solenoid valve 2410 betweenthe normally open position, which allows pilot gas flow through itsoutlet 2412 to the gas sparing valve 330, and the closed position, inwhich the solenoid 2410 stops pilot flow to the outlet 2412 and to thegas sparing valve 300 at the control side 333. In the closed position ofthe electronic solenoid 2410, flow is closed at inlet 2411, but flow isthen opened at the vent 2414, which allows the pilot control line 320Dto vent and the pressure at the control side 333 to drop to P_(atm),thereby closing the gas sparing valve 330 and stopping flow in the maingas side 310. The electronic timer 2423 cycles the solenoid valve 2410between the closed and open state creating a controlled auto breathfunction that can be user adjusted for on time and off time. Thisoperation continues until the valve/switch actuator 2603 is set back tothe manual position by way of the toggle 2603A.

It is to be understood that the gas sparing circuit 2400 may be modifiedas described herein to provide for CPAP functionality as shown in FIG. 4and/or to include an internal gas supply, as shown in FIG. 25.

Now turning to FIG. 26B, there is illustrated a block diagram for yetanother exemplary embodiment of a gas sparing circuit 2600′, inaccordance with an exemplary embodiment of the present invention. Thisgas sparing circuit 2600′ includes both the manual pilot controlfunctionality of FIGS. 3 and 4 (the gas sparing circuit 400) and theelectrical switch-activated pilot control of FIG. 24 (the electricallycontrolled solenoid pilot valve 2410) for auto breath capability withthe exception that the electrical switch-activated pilot control valve2410 is located in a removable accessory enclosure 2650 external to thegas sparing circuit 400 and is attached to the pilot control port 116 atoutlet 112. An electrical switch 2655 in the accessory enclosure 2650activates the electronic pilot circuit control.

The gas sparing circuit 2600′ incorporates a gas sparing configurationidentical to the gas sparing circuit 400 shown in FIG. 4 and includesthe resuscitation side 410 and the CPAP side 420. In addition toincluding the gas sparing circuit 400, the gas sparing circuit 2600′further includes the removable auto breath control module 2650 connectedto the outlet port 116 of the gas sparing circuit 400. The removableauto breath control module 2650 includes its own pilot control port116′. When not installed, the breathing circuit 120 or 120′ can beattached to the gas port 112 (described above with respect to FIG. 4).When the auto breath control module 2650 is attached to the pilotcontrol port 116, the pilot control line 365 of the breathing circuit120 or 120′ can still be connected to the pilot control port 116′ formanual operation.

The auto breath control module 2650 includes an inlet line 2651, whichconnects to the pilot control port 116, and an outlet line 2652, whichconnects to a pilot outlet port 116′. An electronic solenoid valve 2410is connected between the inlet and outlet lines 2651 and 2652.Specifically, an inlet 2411 of the electronic solenoid valve 2410 isconnected to the inlet port 2651, and an outlet 2412 of the electronicsolenoid valve 2410 is connected to the outlet port 2652. A timercircuit 2433 is connected to the electronic solenoid valve 2410 throughwires 2424 and to a control switch 2655 via wires 2654. The pilotcontrol line 365 of circuit 120 connects to outlet port 116′ of the autobreath control module and provides for manual control.

Operation of the gas circuit 2600′ of FIG. 26B, with manual pilotcontrol and electrical switch-activated pilot control for auto breathcapability, is now described. The external auto breath module 2650 isattached to the gas control circuit 410 through the inlet line 2651 ofthe auto breath control module 2650 which is connected to the pilot port116 of the main gas circuit 410. The output line 2652 is provided fromthe auto breath control module 2650 for connection to the pilot controlline 365 of breathing circuit 120. For operation of gas circuit 2600′,the main gas line 355 of breathing circuit 120 is connected to outletport 117, as described with respect to FIGS. 3 and 4. The pilot controlline 365 of breathing circuit 120 is connected to the outlet port 116′of the auto breath control module 2650.

When the auto breath control module control switch 2655 is in the Offposition the electronic solenoid valve 2410 is in the normally openposition allowing pilot gas to flow unrestricted through the solenoidvalve 2410. Then operation of the gas sparing circuit 2600′ is identicalin operation to that described in FIGS. 3 and 4 with manual control ofthe main gas line 320 provided through activation of the pilot controlswitch 125.

If auto breath functionality is desired, the control switch 2655 on theauto breath control module 2650 is switched to the On position. Thetimer circuit 2423 is energized and then cycles the solenoid valve 2410from the normally open position to the normally closed position. Thepilot line 320C is then occluded at solenoid input 2651 and pilot gasflow is directed into the pilot control line 320D. Pilot gas at pressureP_(B) is applied to the control side 333 of the gas sparing valve 330,and the valve 330 opens allowing gas to flow into the main gas side 310,as described above with respect to FIGS. 3, 6, and 7. The solenoid valve2410 remains activated, and main gas continues to flow until the timer2423 cycles the solenoid valve 2410 to the normally open position, atwhich time the solenoid valve 2410 vents the pilot line 320C through thesolenoid valve to the pilot control line 365 and out vent port 351 onthe mask switch 125. At this time pressure in the control side 333 ofthe gas sparing valve 330 drops to P_(atm), and the gas sparing valve330 closes, thereby stopping main gas flow through the circuit 310. Theelectronic timer 2423 cycles the solenoid valve 2410 between the closedand open state to create a controlled auto breath function that can beuser adjusted for on time and off time. This operation continues untilthe control switch 2655 is set back to the Off position.

It is to be understood that an alternate embodiment for the externalelectronic auto breath control module 2650 would be to utilize pneumatictimers such as those illustrated in FIG. 10, FIG. 27, and FIGS. 28 and29, and a pneumatic valve/switch as necessary but in a configurationwhere the pneumatic timers would be located within an external removablemodule, as described in FIG. 26B. In another exemplary embodiment, CPAPbranch portion 430B could be connected to main branch portion 310Ballowing the pressure relief valve 118 to be disposed downstream of theconnection with the portion 430B. In such embodiment, the pressurerelief valve 118 provides venting for overpressure in either the CPAPbranch 430 or the primary branch 310. Furthermore, it is to beunderstood that the gas sparing circuit 2400′ may be modified to includean internal gas supply.

FIG. 27 illustrates still another exemplary embodiment of a gas sparingcircuit, generally designated as 2700, in accordance with an exemplaryembodiment of the present invention. This gas sparing circuit 2700includes both pneumatic manual pilot control functionality through theattached circuit and automatic pneumatic timer based auto breath controlset with a switch on the gas control unit instead of having to hold themanual pilot line occluded. Once switched to automatic, the gas sparingcircuit 2700 cycles pneumatically until the switch is set back to manualor gas pressure removed from the pilot line. This gas sparing circuit2700 includes both the manual pilot control functionality of FIG. 3 (themanual pneumatic pilot control line 365 and the pilot air flow controlswitch 125) and the pneumatic timer pilot control of FIG. 10 for autobreath capability.

Operation of the gas sparing circuit 2700, with manual pilot control andpneumatic timer activated pilot control for auto breath capability, isnow described. Operation of the gas sparing circuit 2700 is identical inoperation to the gas sparing circuit 300 in FIG. 3 when the pneumaticvalve/switch actuator 2702 is in the manual control position forutilization of the pilot circuit portion 320C in conjunction with pilotcontrol line 365 and flow control switch 125. In this configuration,when the pneumatic valve/switch actuator 2702 is set in the manualposition the pneumatic timers 1010 and 1020 are not active and pilotflow bypasses the timers and is directed to pilot control line 320C.When the pilot control line 365 is occluded by use of flow controlswitch 125, pilot circuit 320C is also occluded allowing pilot gas toflow through line 2701B and into pilot line 320D. Pilot gas at pressurePB is applied to the control side 333 of the gas sparing valve 330 andthe valve opens allowing gas to flow into the main gas side 310 asdescribed above with respect to FIGS. 3, 6, and 7. Releasing mask switch125 causes the pressure to drop in pilot line 320D and at control side333 of the gas sparing valve and the valve closes stopping gas flow intothe main gas side 310 as described above with respect to FIGS. 3, 6, and7. When the pneumatic valve/switch actuator 2702 is set in the autobreath position, the pneumatic timer circuit is activated and autobreath operation occurs in an automatic manner. When the pneumaticvalve/switch actuator 2702 is set in the auto breath position pilot gasis directed to the pneumatic timer through line 1030A and operationoccurs in the same manner as described with respect to gas sparingcircuit 1000 in FIG. 10. At this time the pneumatic timers 1010 and 1020begin to cycle the pilot gas flow on and off based on used selected timesettings, to the gas sparing valve 330. In the first part of the timercycle pilot gas is directed from the timer circuit through line 1030E topilot line 320D and at control side 333 of the gas sparing valve 330 andthe valve opens to allow gas flow through main gas side 310. In thesecond part of the timer cycle pilot gas flow is stopped to the gassparing valve 300 at control side 333 which allows the pilot controlline 320D to vent and the pressure at control side 333 to drop to Patm,closing the gas sparing valve 330 and stopping flow in the main gas side310. The pneumatic timers 1010 and 1020 cycles the gas sparing valve 330between the closed and open state creating a controlled auto breathfunction that can be user adjusted for on time and off time. Thisoperation continues until the pneumatic valve/switch actuator 2702 isset back to the manual position or gas pressure is removed from thepilot line.

It is to be understood that the gas sparing circuit 2700 may be modifiedas described herein to provide for CPAP functionality as shown in FIG. 4and/or to include an internal gas supply.

FIG. 28 illustrates a block diagram for a further exemplary embodimentof a gas sparing circuit 2800, in accordance with an exemplaryembodiment of the present invention. This gas sparing circuit is similarto the gas sparing circuit 1000 illustrated in FIG. 10. As describedherein, the gas sparing circuit 1000 uses an on-timer 1020 and anoff-timer 1030 to control the auto breath circuit 1000. The gas sparingcircuit in FIG. 28 uses two on-timers 2820, 2830, and a 4-way spoolvalve 2810 to effectively make one on-timer (the on-timer 2830) and anoff-timer (the other on-timer 2820), without having to use a realoff-timer, to control the pneumatically timing circuit 2800. The resultis a gas sparing circuit that has the same control of inhalation andexhalation breath as the circuit 1000. In this gas sparing circuit 2800,as in the gas sparing circuit 1000, auto breath operation is activatedthrough occlusion of the pilot line 365 at switch 125. Auto breathfunction stops when the pilot line 365 is un-occluded at mask switch125.

It is to be understood that the gas sparing circuit 2800 may be modifiedas described herein to provide for CPAP functionality as shown in FIG. 4and/or to include an internal gas supply.

FIG. 29 illustrates and describes a block diagram for another exemplaryembodiment of a gas sparing circuit 2900, in accordance with anexemplary embodiment of the present invention. This gas sparing circuitis similar to the gas sparing circuit 2700 in FIG. 27 but uses twoon-timers 2820 and 2830 and a 4-way spool valve 2810 to effectively makeone on-timer (the on-timer 2830) and one off-time (the off-timer 2620),without having to have a real off-timer, to control the pneumaticallytiming circuit 2900. As with gas sparing circuit 2700 in FIG. 27, thefunction of the gas sparing circuit is activated by pneumaticvalve/switch 2702 so that manual pilot control is still possible withthis gas sparing circuit but the circuit can be switched into automaticauto breath mode without having to hold the external pilot line 365occluded.

It is to be understood that the gas sparing circuit 2700 may be modifiedas described herein to provide for CPAP functionality as shown in FIG. 4and/or to include an internal gas supply.

An exemplary feature which may be added to any of the exemplaryembodiments of the gas sparing circuits described herein. In any of thegas sparing circuits having manual pilot control lines 365, a latch canbe added to the switch 125 or 1340 or 2425 to allow the switch to beheld closed without the need for the user to apply constant pressure tothe switch 125 or 1340 or 2425. This latch may be desirably used forauto breath modes to allow the user to not have to hold the switch 125or 1340 or 2425 down continuously.

Now referring to FIG. 30, there is illustrated an exemplary embodimentof a gas sparing circuit 3000 which functions similarly to the gassparing circuit 300 of FIG. 3, but further includes a pressure surgedamper configuration, in accordance with an exemplary embodiment of thepresent invention. The pressure surge damper configuration comprises aseries of damping elements comprising reducing elements 3020, reducedtube ID sections 3040, and expansion elements 3030 in exemplarypositions to dampen gas pressure surges that may occur in the main gasline 310B when the gas sparing valve 330 opens. It is to be understoodthat this pressure surge damper configuration may be added to any of theexemplary gas sparing circuits described herein.

Operation of the pressure surge damper configuration using reducingelements 3020, reduced ID elements 3040, and expansion elements 3030 isnow described. Referring to FIG. 30, as the gas sparing valve 330 openspressurized gas quickly flows into the main gas line 310B. This instantrelease of pressurized gas flow can create a pressure wave front in themain gas line 310C, 310D and 310E that may be slightly higher than thesteady state pressure after the gas sparing valve 330 has been openedfor a period of time. It may therefore be beneficial to dampen thispressure surge using a pressure surge damper system containing dampingelements 3020, 3030 and 3040 as illustrated. As the gas pressure frontmoves along main gas line 310B it encounters the reducer element 3020 inthe main gas line. The gas pressure enters the reducer 3020 where theflow path ID is decreased abruptly creating a velocity increase in thegas flow and a turbulence effect. The gas flow then traverses through areduced ID flow element 3040 and then enters an expansion element 3030where the flow path ID is increased abruptly creating a velocitydecrease and a second turbulent effect which combines to reduce thepressure wave an incremental amount. Additional elements located at3020′, 3030′ and 3040′ and at 3020″, 3030″ and 3040″ are added tofurther dampen the pressure surge to the desired level. By combining aseries of these elements in series, or if desired in parallel, thepressure wave front can be either partially suppressed or fullysuppressed as desired. As the initial pressure surge damper elements3020, 3030, and 3040 act to dampen the pressure wave front, the main gaswith a reduced pressure wave progresses through main gas line 310C′ toline 310D and then to damping elements 3020′, 3030′ and 3040′ where thepressure wave front is reduced further. The main gas then progressesthrough main line 310D′ with even further reduction in the amplitude ofthe pressure wave front to main line 310E. The gas then interacts withthe damping element 3020″, 3030″ and 3040″ where again the pressure wavefront is further reduced to the point where it is totally eliminated andthe main gas, without the pressure wave front, then progresses to thereaming main gas lines 310E′ and into the breathing circuit 120 atoutlet 117. When the gas sparing valve 330 is closed, and the gas flowin the main gas line 310B ceases. The pressure surge damperconfiguration is then ready for the next pressure wave.

In an exemplary alternative embodiment, a pressure surge damper 3010 maybe used in place of or in addition to the dampening elements illustratedin FIG. 30 and described above. FIG. 30A illustrates an exemplaryembodiment of the damper 3010, in accordance with an exemplaryembodiment of the present invention. The pressure surge damper containsa base 3027, with inlet port 3021, a pliant damper diaphragm 3023, aspring 3024, a vent control valve 3025 with vent port 3026, and a cap3028. The diaphragm 3023, cap 3028, and base 3027 interact to create asealed damper chamber 3022. This pressure damper is shown in theunpressurized state.

Operation of the pressure surge damper 3010 is now described. Referringto FIGS. 30 and 30A, as the gas sparing valve 330 opens pressurized gasquickly flows into main gas line 310B. This instant release ofpressurized gas flow can create a pressure wave front in the main gasline 310C, 310D and 310E that may be slightly higher than the steadystate pressure after the gas sparing valve has been opened for a periodof time. It may therefore be beneficial to dampen this pressure surgeusing a pressure surge damper 3010 as illustrated. As the gas pressurefront moves along main gas line 310B it encounters the pressure surgedamper 3010 at a 90 degree bend in the main gas line. The gas pressureenters the inlet port 3021 of the pressure surge damper and encountersthe pliant damper diaphragm 3023. The gas pressure fills the sealeddamper chamber 3022 and forces the damper diaphragm to expand and moveagainst the spring 3024. The air trapped behind the pliant diaphragm iscompressed and in a controlled manner exits through the vent port 3026.The vent control valve 3025 controls the rate at which the air can bevented from the space behind the pliant diaphragm and thus the rate atwhich the pliant diaphragm can expand and move against the spring. Thepliant diaphragm 3023 in combination with the spring 3024 and the ventcontrol valve 3025 act together to create a controlled damping effect onthe main gas entering the inlet port. As the pressure surge damper 3010acts to dampen the pressure wave, the pliant diaphragm 3023 reaches itsfull equilibrium travel and the main gas without the pressure wave thenprogresses to the reaming main gas lines 310C, 310D, 310E and into thebreathing circuit 120. When the gas sparing valve 330 is closed, and thegas flow in the main gas line 310B ceases, the pliant diaphragm 3023returns to its original unpressurized condition by reaction force of thespring 3024. The pressure surge damper is then ready for the nextpressure wave.

FIGS. 31A and 31B illustrate the damping effect of the pressure surgedamper 3010 in the gas sparing circuit 3000. FIG. 31A illustrates thepressure in the main gas line after the time T₁ that the gas sparingvalve 330 opens without the pressure surge damper. The pressure in themain gas line 310 increase quickly to P₂ which is the surge pressure andis above the steady state pressure P₁. The pressure then drops at timeT₂ to the steady state pressure P₁. FIG. 31B illustrates the pressure inthe main gas line after the time T₁ that the gas sparing valve 330 openswith the pressure surge damper. The pressure in the main gas line 310 isdamped and slowly increases to P₁, the steady state pressure at time T₂.The pressure wave in the main gas line 310 is suppressed and no pressurespike occurs at the breathing circuit 120.

FIG. 32 illustrates an exemplary alternative embodiment of theendotracheal (ET) hand piece 1500 of FIG. 15, generally designated as1500′ in FIG. 32, in accordance with an exemplary embodiment of thepresent invention. The ET hand piece 1500′ includes several similaritieswith the ET hand piece 1500. For example, the inlet port 1530 of the EThand piece 1500′ is configured to be connected to the rotating outletport 1220 of the mask connection 1200, and the outlet port 1550 of theET hand piece 1500′ is configured to be connected to the endotrachealtube 1560. Furthermore, the ET hand piece 1500′ includes the pilotcontrol switch 1340′, as does the ET hand piece 1500, but furtherincludes a CPAP vent port 1700′ containing the CPAP valve 1706′ and portcap 1704′ as described in FIGS. 22 and 23, which the ET hand piece 1500does not contain. When used in conjunction with the gas sparing circuit400 of FIG. 4 set to CPAP mode, the port cap 1704′ is removed from thevalve housing 1702′ and CPAP functionality is possible.

It is to be understood that the ET hand piece 1500′ may be modified asdescribed herein to include electrical wires such as those illustratedin FIG. 24, element 2465, and an electrical switch similar to switch2425 in FIG. 24 to allow functionality with the gas sparing circuit 2400shown in FIG. 24.

Because the various embodiments of the gas sparing systems, devices, andcircuits described herein provide for control of main (primary) gas,large continuous gas flows are minimized, and gas is conserved. Inaddition, the gas sparing systems, devices, and circuits describedherein allow for precise pressure and volume control. Several examplesof patient interfaces, such as the masks 130, 130′, 130″, and 130′″ andET hand pieces 1500 and 1500′, are described herein for delivering thegas to a patient. It is to be understood that the patient interfaces arenot limited to these examples.

These and other advantages of the present invention will be apparent tothose skilled in the art from the foregoing specification. For example,it is contemplated that the gas sparing valve 330 and the pilot controlline 365 may be replaced, respectively, by an electronically controlledvalve and a switch coupled to the valve via a conductor for selectivecontrol of the valve. Further, the pneumatic timer controls may bereplaced by electrical timer controls. Accordingly, it is to berecognized by those skilled in the art that changes or modifications maybe made to the above-described embodiments without departing from thebroad inventive concepts of the invention. It is to be understood thatthis invention is not limited to the particular embodiments describedherein, but is intended to include all changes and modifications thatare within the scope and spirit of the invention.

What is claimed is:
 1. A system for delivering gas to a patient,comprising: a gas control unit comprising an outlet comprising a maingas line outlet, the gas control unit further comprising a gas sparingcircuit comprising a primary branch coupled to the main gas line outlet,the primary branch comprising a gas sparing valve for controlling a flowof gas through the primary branch; a breathing circuit comprising a maingas line comprising a first end and a second end, the first end of themain gas line coupled to the main gas line outlet; a pilot controlswitch for selectively causing the gas sparing valve to provide the flowof gas to the main gas line via the main gas line outlet; and a patientinterface coupled to the second end of the main gas line of thebreathing circuit.
 2. The system of claim 1, wherein: the outlet of thegas control unit further comprises a pilot control line outlet, thebreathing circuit further comprises a pilot control line coupled to thepilot control line outlet, the pilot control switch is a pneumaticcontrol switch for selectively occluding the pilot control line, the gassparing circuit further comprises a pilot control branch coupled to thepilot control line outlet, and the gas sparing valve is a pneumaticcontrol valve disposed in the primary branch, the pilot control switchconfigured to actuate the pneumatic control valve based on the selectiveocclusion of the pilot control line by the pneumatic control switch toprovide the flow of gas to the main gas line via the main gas lineoutlet.
 3. The system of claim 2, wherein the patient interface is amask coupled to the second end of the main gas line of the breathingcircuit, and the pneumatic control switch is disposed on the mask. 4.The system of claim 2, wherein the patient interface is an endotrachealtube adapter for connection to an endotracheal tube, and the pneumaticcontrol switch is disposed on the endotracheal tube adapter.
 5. Thesystem of claim 1, wherein: the gas control unit further comprises anelectric solenoid control valve and an electrical pilot control lineinput, the breathing circuit further comprises an electrical pilotcontrol line, and the pilot control switch is an electrical controlswitch coupled to the electrical pilot control line for selectivelycontrolling the electric solenoid control valve to control the gassparing valve to provide the flow of gas to the main gas line via themain gas line outlet.
 6. The system of claim 5, wherein the patientinterface is a mask coupled to the second end of the main gas line ofthe breathing circuit, and the electrical control switch is disposed onthe mask.
 7. The system of claim 5, wherein the patient interface is anendotracheal tube adapter for connection to an endotracheal tube, andthe electrical control switch is disposed on the endotracheal tubeadapter.
 8. The system of claim 1, wherein: the gas control unit furthercomprises a continuous positive airway pressure (CPAP) branch coupled tothe main gas outlet, and a mode-selection switch for selectivelydirecting source gas to the CPAP branch or to the gas sparing circuit,and the patient interface is a mask coupled to the second end of themain gas line of the breathing circuit, the mask comprising a CPAPexhalation port.
 9. The system of claim 1, wherein the gas control unitfurther comprises an internal air supply that sources the flow of gas tothe main gas line, and wherein the primary branch is further coupled tointernal air supply.
 10. The system of claim 1, wherein the pilotcontrol switch is a pneumatic-mechanical timer-based trigger.
 11. A gascontrol unit for delivering gas to a patient, comprising: an outletcomprising a main gas line outlet; and a gas sparing circuit comprising:a primary branch coupled to the main gas line outlet; and a gas sparingvalve for controlling a flow of gas to the main gas outlet in responseto a selective control.
 12. The gas control unit of claim 11, wherein:the outlet further comprises a pilot control line outlet, the gassparing circuit further comprises a pilot control branch coupled to thepilot control line outlet, and the gas sparing valve is a pneumaticcontrol valve comprising a pneumatic control input coupled to the pilotcontrol branch, the pneumatic control valve disposed in the primarybranch and configured to actuate in response to the selective control toprovide the flow of gas to the main gas line outlet.
 13. The gas controlunit of claim 12, further comprising a first pneumatic timer controldisposed in the pilot control branch, the first pneumatic timer controlconfigured to control an on-time of the pneumatic control valve inresponse to the selective control to provide the flow of gas to the maingas line outlet.
 14. The gas control unit of claim 13, furthercomprising a second pneumatic timer control disposed in the pilotcontrol branch, the second pneumatic timer control configured to controlan off-time of the pneumatic control valve in response to the selectivecontrol to provide the flow of gas to the main gas line outlet.
 15. Thegas control unit of claim 11, wherein: the gas control unit furthercomprises an electrical pilot control line input, the gas sparing valveis controlled by an electric solenoid control valve disposed in thepilot branch, the electric solenoid control valve configured to actuatein response to the selective control to actuate the gas sparing valve toprovide the flow of gas to the main gas outlet.
 16. The gas control unitof claim 15, further comprising an electrical timer control configuredto receive the selective control via the electrical pilot control lineinput and to control an on-time and an off-time of the electric solenoidcontrol valve in response to the selective control to provide the flowof gas to the main gas line outlet.
 17. The gas control unit of claim11, further comprising a continuous positive airway pressure (CPAP)branch coupled to the main gas outlet, and a mode-selection switch forselectively directing source gas to the CPAP branch or to the gassparing circuit.
 18. A patient interface for use with a gas sparingcircuit for delivering gas to a patient, comprising: an output fordelivering the gas to the patient; an input for receiving the gas from asource; and a control switch for selectively controlling the delivery ofthe gas to the patient.
 19. The patient interface of claim 18, whereinthe control switch is a pneumatic switch configured for selectivelyoccluding a pilot control line to control the delivery of the gas to thepatient.
 20. The patient interface of claim 18, wherein the controlswitch is an electric switch configured for selectively causing a gassparing valve to be actuated to control the delivery of the gas to thepatient.